PLEASE HELP ME URGENT​

PLEASE HELP ME URGENT

Answers

Answer 1

Here's the solution,

A.) calculate work done :

we know,

[tex]weight \: = mass \times acceleration[/tex]

[tex]weight = 10 \times 10[/tex]

[tex]weight = 100 \: Newtons[/tex]

And,

[tex]work \: done = force \times dispacement[/tex]

[tex]work \: done = 100 \: \times \: 20[/tex]

[tex]work \: done = 2000 \: joules[/tex]

B.) find power :

[tex]power = \dfrac{work \: done}{time} [/tex]

[tex] power = \dfrac{2000}{2} [/tex]

[tex]power = 1000 \: watt[/tex]
Answer 2

Answer:

work done=2000J and power=1000w

Explanation:

(a) Work done= Gravitational potential energy

W=mgh

Data,

m=10kg

h=20m

g=10N/kg

W=10kg*10N/kg*20m

W=2000J or 2kJ

(b). power=work done/time

P=2000/2

P=1000w


Related Questions

Two equally charged pith ball are 3cm apart in air and repel each other with a force of 4X105N - Comput the charge on each bali-​

Answers

TheThe charge applied on each ball is 2 X 10∧-9 C.

Define force ?

An object with mass can change its velocity, or accelerate, as a result of a force. An obvious way to describe force is as a push or a pull. A force is a vector quantity since it has both magnitude and direction.

The pitch balls repent each other with force

F= 4 X 10^-5N

Let the charge on each ball be Q.

4 X 10^-5= k(Q)(Q) /  (3 X 10^-2)^2

Q^2= 4*10^-5X 9*10^-4 / 9*10^9

Q^2 = 4 X 10^-18

Q= √4 X 10^-18

Q = 2 X 10^-9 C.

Therefore, the charge on each ball is 2X10^-9C.

To know more about Force visit:

brainly.com/question/13191643

#SPZ1

Each ball has been charged with 2 X 10⁹ C. When a product is held in electrostatic energy, its properties referred to as electric discharge allows it to feel force.

What is force?

A force can compel a heavily armored item to increase or modify overall velocity. A push or a pull is a simple and effective method to explain force. That's because a force has both magnitude and direction it is a dimensionless number.

The pitch balls repent each other with force

F = 4 X 10⁻⁵N

4 X 10⁻⁵ = k(Q)(Q) /  (3 X 10⁻²)²

⇒ Q²      = 4 × 10⁻⁵ X   9 × 10⁻⁴ / 9 × 10⁹

⇒ Q²      = 4 X 10⁻¹⁸

⇒ Q        = √4 X 10⁻¹⁸

⇒ Q        = 2 X 10⁻⁹ C.

Therefore, the charge on each ball is 2 X 10⁻⁹C.

To know more about Force visit :-

https://brainly.com/question/13191643

#SPJ1

What is the meaning of the density of states function?

Answers

Ans-The density of states function describes the number of states that are available in a system and is essential for determining the carrier concentrations and energy distributions of carriers within a semiconductor.

Answer:

density equal to mass upon volume

simple definition

A cannonball is launched with an initial speed of 20 m/s. Calculate the maximum height the ball could reach.

Answers

Answer:

During its trajectory the cannon ball will have kinetic and potential energy

E = KE + PE

The maximum value of PE will occur when the cannon ball was fired straight up - for other trajectories PE will be less because of translational KE

So E = M g h = 1/2 M v^2    for maximum height

h = v^2 / (2 * g) = 400 / (2 * 9.8) = 20.4 m

A man drags a 10.0 kg bag of mulch at a constant speed applying a 22.5 N force at a 32-degree angle. What is the friction force acting on the bag?

Answers

The

friction

force acting on the bag is 4.36µ.

What is friction force?

The

force

preventing sliding against one another of solid surfaces, fluid layers, and material components is known as friction.

Given,

Force =F=22.5 n

Mass=m= 10 kg

mu=µ=?                            

(1N= 1kg m/s²)

Gravitational force =g= 9.81 m/s²

As we know,

F= µ*m*g

µ= m*g/F

  = 10*9.81/ 22.5

µ= 4.36 .

Therefore, the friction force acting on the bag is 4.36.

To know more about

Force

visit:

brainly.com/question/26115859

#SPZ1

The bag is subject to a friction force of 4.36. A man applies a 22.5 N force at a 32° angle while dragging a 10.0 kilogram bag of mulch at a steady speed.

How much friction is there?

Friction refers to the force that resists hard surface, fluid layering, and materials ingredients from gliding past one another. Friction lessens a machine's mechanical advantage, or, to put it another way, friction decreases the output to input ratio.

Force = 22.5 N

Mass  = 10 kg

⇒ mu     = µ (1N= 1kg m/s²)

⇒ g        = 9.81 m/s²

As we know, F= µ × m × g

⇒ µ = (m × g)/F

⇒ (10 × 9.81)/ 22.5

⇒ µ = 4.36 .

Therefore, the friction force acting on the bag is 4.36.

To know more about Force visit :-

https://brainly.com/question/13191643

#SPJ1

A satellite is a large distance from a planet, and the gravitational force from the planet is the only significant force exerted on the satellite. The satellite begins falling toward the planet, eventually colliding with the surface of the planet. As the satellite falls, what claims is correct about how the force that the planet exerts on the satellite Fps changes and how the force that the satellite exerts on the planet Fsp changes, if at all? What reasoning supports this claim?

Answers

Answer:

The answer is "Option A".

Explanation:

Please find the complete question in the attached file.

The strength is equal due to the third law of Newton, and [tex]Fsp = Fps = \frac{Gmsmp}{r^2}\[/tex], therefore the force increases with decreased separation r.

Three point charges q1 = +2 μC, q2 = −3 μC, and q3 = +4 μC are located at the corners of a right angle triangle as shown below. Find the magnitude and direction of the resultant force on q3.

Answers

Answer:

Explanation:

4

The magnitude and direction of the resultant force on q3 is;

F_net = 32.2 N in the direction of q3

We are given;

q1 = +2 μC = 2 × 10^(-6) C

q2 = -3 μC = -3 × 10^(-6) C

q3 = +4 μC = 4 × 10^(-6) C

Now,from the given image, charges q1 and q2 attract charge q3.

Formula for force on a charge is;

F = (kq1 * q2)/r²

Where;

k = 9 × 10^(9) N.m²/C²

Thus;

F_y = kq1*q3/(r1)²

We have;

q1 = 2 × 10^(-6) C

r1 = 5 cm = 0.05 m

q3 = 4 × 10^(-6) C

Thus;

F_y = (9 × 10^(9) × 2 × 10^(-6) × 4 × 10^(-6))/(0.05^(2))

F_y = 28.8 N

Similarly;

F_x = kq2*q3/(r2)²

r2 = 5/(tan 30)

r2 = 8.66 cm = 0.0866 m

F_x = (9 × 10^(9) × -3 × 10^(-6) × 4 × 10^(-6))/(0.0866^(2))

F_x = -14.4 N

Thus, magnitude of resultant force is;

F_net = √((28.8)² + (-14.4)²)

F_net = √1,036.8

F_net = 32.2 N

Read more at; https://brainly.com/question/16796365

8. Jane rides a sled down a slope of angle θ at constant speed v. Determine the coefficient of kinetic friction between the sled and the slope. Neglect air resistance.
(A) μ=gsinθ (B) μ=mgcosθ (C) μ=tanθ (D) μ=gcosθ

Answers

Answer:ssssw

Explanation:

Which situation would deplete freshwater?

Answers

Answer:

If freshwater consumption was greater than freshwater renewal.

Explanation:

Similar to another Brainly answer :O

The slope of a velocity time graph will give___

Answers

Answer:

THE ANSWER IS ( acceleration of the object )

What are the horizontal and vertical components of a cat's displacement when the cat has climbed 5 m
directly up a tree © = 90°? Sin90=1
cos90=0

Answers

The horizontal component of the cat's displacement, Dx = 0 m

The vertical component of the cat's displacement, Dy = 12 m

What are the horizontal and vertical components of a vector?

The horizontal component of a vector is the value of that vector acting in the horizontal direction.

The horizontal component of a vector is given as Dx.

Dx = Dcosθ

where;

D is the resultant of the vector

θ is the angle of the vector from the horizontal

The horizontal component of the cat's displacement is:

Dx = 12 * 0

Dx = 0 m

The vertical component of a vector is the value of that vector acting in the vertical direction.

The vertical component of a vector is given as Dy.

Dy = Dsinθ

where;

D is the resultant of the vector

θ is the angle of the vector from the horizontal

The vertical component of the cat's displacement is:

Dy = 12 * 1

Dy = 12 m

Learn more about horizontal and vertical components at: https://brainly.com/question/26446720

#SPJ1

how to prepare a trading stock account​

Answers

Answer:

Opening stock details of raw material, semi-finished goods and finished goods.

Closing stock details of raw material, semi-finished goods, and finished goods.

Total purchases of goods fewer Purchase Returns.

Total sales of goods fewer Sales Returns.

Which of the following correctly describes the order of skin layers from the inside to the outside of the body?
A. dermis, epidermis, hypodermis
B. hypodermis, dermis, epidermis
C. epidermis, hypodermis, dermis
D. hypodermis, epidermis, dermis

Answers

Answer:

it is a

Explanation:

dermis,epidermis,hypodermis

Answer:

B. hypodermis, dermis, epidermis

this is because it is inside to outside

hypodermis is deeper tissue, dermis is beneath epidermis, and epidermis is the outermost layer

The momentum of an object is determined to be 7.2×10-3 kg⋅m/s. Express this quantity as provided or use any equivalent unit. (Note: 1 kg = 1000 g

Answers

The mass of the moving item is referred to as momentum. There is magnitude and direction to momentum. The object has a momentum of 7.2 g-m/s.

What is the momentum of an object?

Momentum is a vector quantity that is created during motion by an object's mass and velocity. Thus, momentum will be expressed in units of kg-m/s.

Considering that item has motion. Likewise, 1 kilogram equals 1000 g. Therefore, the momentum will transform into units of grams when we enter the value of 1 kg.

Momentum = 7.2 x 10⁻³ 1000g-m/s

Momentum = 7.2 g-m/s.

Thus, we may deduce that the object's momentum, measured in grams per second, is 7.2 g-m/s.

Learn more about momentum, here:

https://brainly.com/question/24030570

#SPJ1

True or False? 13. All living things are made of cells 14. All cells have DNA within their nucleus 15. The cell is the basic unit of life in all organisms 16. All cells in a living thing are similar in structure or function 17. Cells must develop from other cells

Answers

Answer:

1: True

2: False

3: True

4: False

5: True

How important do you think temperature, radiation, and geologic activity are to the habitability in general?

Answers

Answer:

Explanation:

All 3 are critical for habitability

What is the speed of a transverse wave in a rope of length 2 meters and mass 0.06
kg under a tension of 500 nt?

Answers

Answer:

16.3 wave speed.

Explanation:

50 POINTS !!!

Three particles of mass 8 kg, 3 kg, and 7 kg are connected by rigid rods of
negligible mass lying along the y axis and are placed at 5 m, -2 m, and -6 m,
respectively as in the figure. The system rotates about the x axis with an angular
speed of 1.65 rad/s.

a) Find the moment of inertia about the x axis. Consider the
masses to be point particles.

b) Find the total rotational energy.

c) Find the linear speed of the top particle of mass 8 kg in the figure.

Answers

Answer:

a) I = 464 kg m²,  b)  K = 631 .6 J, c)  v = 8.25 m / s

Explanation:

a) the moment of inertia of point particles is

          I = ∑ m_i r_i²

in this case

          I = 8 5² + 3 (-2) ² + 7 (-6) ²

          I = 464 kg m²

b) The kinetic energy is

          K = ½ I w²

          K = ½ 464 1.65²

          K = 631 .6 J

c) linear and angular velocity are related

          v = w r

          v = 1.65 5

          v = 8.25 m / s

What is electronic dispersion theory?

Answers

Dispersion in wave theory is the phenomena where a wave's phase velocity changes depending on its frequency. The article can explore different definitions. This is the typical definition for dispersion (waves).

When sinusoidal waves with various wavelengths propagate at various speeds, a wave packet with mixed wavelengths has a tendency to disperse in space. Dispersion in wave theory is the phenomena where a wave's phase velocity changes depending on its frequency.

The article can explore different definitions. This is the typical definition for dispersion (waves).

A full set of approximate solutions to the one-electron Schrödinger equation are found in a three-dimensional atomic lattice that is randomly filled with atoms of different kinds and has, on average, the periodicity of a Bloch wave.

Equations are provided that enable the calculation of each wave's energy, average behavior, absent a phase factor, close to any sort of atom, and damping parameter.

A comparison is made between a periodic lattice with a complicated, energy-dependent potential and a random A-B lattice. The dispersion relation of the system is obtained by solving the eigenvalue problem in this potential using any of the established techniques for periodic potentials.

To learn more about Dispersion theory from given link

https://brainly.com/question/28461293

#SPJ1

define area and give its SI unit

Answers

Answer:

area is the space bounded by certain lines, the SI unit of area is m²

area of rectangle =l×w×h

square=l²

Please need help ASAP, ASAP

Answers

If force is doubled, acceleration will also be doubled.

Newton’s second law of motion, unlike the first law of motion, pertains to the behaviour of objects for which all existing forces are unbalanced. The second law of motion is more quantitative and is used extensively to calculate what happens in situations involving a force.It states that: Force is equal to the rate of change of momentum. For a constant mass, force equals mass times acceleration.The acceleration of the body is directly proportional to the net force acting on the body and inversely proportional to the mass of the body. This means that as the force acting upon an object is increased, the acceleration of the object is increased.

In this given question, force is doubled. We know that force is directly proportional to acceleration. As we increase the force on an object the acceleration increases proportionally. Therefore, if you double the force you double the acceleration.

To know more about force visit:

https://brainly.com/question/15486556

#SPJ1

state the property of plastic that allows it to become electrostatically charged
(please answers ty) ​

Answers

Answer:

when a plastic rod is rubbed with a duster, electrons are transferred from one material to the other. The material that gains electrons becomes negatively charged. The material that loses electrons becomes positively charged.

Check the attached image for the question~

Answers

Answer:

put the full thin g

Explanation:

The planet Mars has a mass that is 0.11 times Earth’s mass and a radius that is
0.54 times Earth’s radius. a) How much would a 60.0-kg astronaut weigh if
she were to stand on the surface of Mars?

Answers

The weight of an object is a measure of the force of gravity acting on that object. The force of gravity is proportional to the mass of the object and inversely proportional to the square of the distance between the object and the center of the gravitational field.

Since the mass of Mars is 0.11 times the mass of Earth and the radius of Mars is 0.54 times the radius of Earth, the gravitational field on Mars is weaker than the gravitational field on Earth. To calculate the weight of the astronaut on Mars, we need to use the formula for gravitational force:

F = G * m1 * m2 / r^2

where F is the gravitational force, G is the gravitational constant, m1 is the mass of the object being attracted, m2 is the mass of the object providing the gravitational field, and r is the distance between the two objects.

Since the mass of the astronaut is m1 and the mass of Mars is m2, we can plug these values into the formula to find the gravitational force on the astronaut on Mars:

F = (6.67 x 10^-11 N*m^2/kg^2) * (60.0 kg) * (0.11 * 5.97 x 10^24 kg) / (0.54 * 6.371 x 10^6 m)^2

Solving this equation, we find that the weight of the astronaut on Mars is approximately 44.4 N, or about 44.4% of her weight on Earth.

A single movable pulley is used to lift 4000N load to the height of 50 cm. If the efficiency of the pulley is 75%, Calculate effort distance,effort applied,output work and mechanical advantage.

Answers

Since the efficiency of the pulley is 75% and the single movable pulley is used to lift 4000N load to the height of 50 cm, the effort distance, effort applied, output work and mechanical advantage are as follows:

Effort Distance = 50 cm

Effort Applied = 5333.33 N

Output work = 2000 J

Mechanical Advantage = 0.75.

When a single movable pulley is used to lift a load, the effort applied is equal to the weight of the load being lifted, and the effort distance is the distance the effort is applied.

Load (output force) = 4000 N

Height lifted = 50 cm = 0.5 m

Efficiency of the pulley = 75%

Given the above information, we can calculate the effort applied, output work, and mechanical advantage as follows:

Effort applied (input force) = Load ÷ Efficiency

= 4000 N ÷ 0.75

= 5333.33 N

Output work = Load x Height lifted

= 4000 N x 0.5 m

= 2000 J

Effort distance = Height lifted

= 50 cm

Mechanical advantage = Load ÷ Effort applied

= 4000 N ÷ 5333.33 N

= 0.75

It is worth noting that pulley efficiency is the ratio of output work to the input work. And since the efficiency of the pulley is 75% so the input work is greater than the output work, which means some of the energy is wasted in overcoming friction and other losses.

Learn more about pulley:

https://brainly.com/question/25855047

The type of heat transfer responsible for your computer leaving your desk very hot after you've used it for awhile?​

Answers

Answer:

Conduction

Explanation:

Conduction is a process whereby heat is transfer through solid state.

True or False question! ⬇⬇ Will give BRAINLIEST!
No matter the medium, light will always bend at the same angle when it passes from one medium to a different medium.
-True
-False

Answers

Answer:

the answer can be probably true since light can be refracted

When a body is accelerated under water, some of the surrounding water is also accelerated. This makes the body appear to have a larger mass than it actually has. For a sphere at rest this added mass is equal to the mass of one half of the displaced water. Calculate the force necessary to accelerate a 10 kg, 300-mm-diameter sphere which is at rest under water at the acceleration rate of 10 m/s2 in the horizontal direction. Use H2O

Answers

Solution :

Mass of the sphere, m = 10 kg

Diameter, D = 300 mm = 0.3 m

Volume of the sphere is [tex]$V=\frac{4}{3} \pi \left(\frac{0.3}{2}\right)^3$[/tex]

                                       [tex]$V=0.01414 \ m^3$[/tex]

So the volume of displaced water, [tex]$V_w=V = 0.01414 \ m^3$[/tex]

Additional mass, [tex]$m_w = \frac{1}{2} \ \rho_w\times v_w$[/tex]

                                  [tex]$=\frac{1}{2} \times 1000 \times 0.01414$[/tex]

                                  [tex]$=7.0686 \ kg$[/tex]

So the total mass, [tex]$M = m_w+m$[/tex]

                                   = 7.0686 + 10

                                   = 17.0686

Force required, F = Ma

[tex]$F=17.0686 \times 10$[/tex]

   = 170.686 N

The force that is necessary to accelerate when the acceleration rate of 10 m/s2 in the horizontal direction should be 170.686 N.

How to calculate the force?

Since Mass of the sphere, m = 10 kg

Diameter, D = 300 mm = 0.3 m

Now volume of the sphere is

V = 4/π (diameter/3)^3

V = 4/3π(0.3/2)^3

= 0.01414m^3

Now the additional mass is

= 1/2* 1000 * volume

= 1/2 *1000*0.01414

= 7.0686

So, the total mass is

= Additional mass + force

= 7.0686 + 10

= 17.0686

Now the force is

= 17.0686 * 10

= 170.686

Hence, The force that is necessary to accelerate when the acceleration rate of 10 m/s2 in the horizontal direction should be 170.686 N.

Learn more about acceleration here: https://brainly.com/question/18555689

A 30-g bullet traveling horizontally at 300 m/s strikes a 1.0-kg block which is attached to a horizontal spring with a force constant of 2000 N/m and rests on a frictionless horizontal surface. The spring is on the far side of the block and aligned with the direction of travel of the bullet. The bullet becomes embedded in the block and, as a result of the impact, and the block slides against the spring. How far is the spring compressed before it reverses its direction of travel

Answers

Answer:

Explanation:

Using law of conservation of momentum during collision , velocity after collision can be found .

common velocity V = m v / ( m + M )

= .030 x 300 / ( .030 + 1 )

V= 8.7378 m /s

The kinetic energy of the bullet and block will be stored as elastic energy

1/2 ( M + m ) V² = 1/2 k A² where k is force constant and A is maximum compression in the spring .

( M + m ) V² =  k A²

1.030 x 8.7378² = 2000 x A²

A² = .0393

A= .1982 m .

= 19.82 cm

Which would help you perform a basketball skill well with
speed?

Answers

The answer would be running in place

How far from the earth must a body be along a line toward the sun so that the sun’s
gravitational pull balances the earth’s? The sun is 9.3 × 107 miles away and its mass is
3.24 × 105 Me.

Answers

Answer:

r = 1.63×10^5 mi

Explanation:

Let r = distance of object from earth

Rs = distance between earth and sun

Ms = mass of the sun

= 3.24×10^5 Me (Me = mass of earth)

At a distance R from earth, the force Fs exerted by the sun on the object is equal to the force Fe exerted by the earth on the object. Using Newton's universal law of gravitation,

Fs = Fe

GmMs/(Rs - r)^2 = GmMe/r^2

This simplifies to

Ms/(Rs - r)^2 = Me/r^2

(3.24×10^5 Me)/(Rs - r)^2 = Me/r^2

Taking the reciprocal and then its square root, this simplifies further to

Rs - r = (569.2)r ----> Rs = 570.2r

or

r = Rs/570.2 = (9.3×10^7 mi)/570.2

= 1.63×10^5 mi

Other Questions
The following information is available for Montrose Company at December 31: Cash in bank account $ 8,540 Petty cash $ 250 Short-term investment (maturing in two months) $ 10,400 Checks from customers $ 1,350 Equipment $ 805 Treasury bill maturing in 60 days $ 10,000 Money orders $ 290 A three-year certificate of deposit maturing in three years $ 6,000 Based on this information, the determine the amount reported as Cash and Cash Equivalents on December 31. A car moving at a constant speed passed a timing device at t=0. After 9 seconds the car has traveled 1,053ft. Write a linear function rule to model the distance in feet d the car has traveled any number of seconds t after passing the timing device. 1.___The enthalpy of the reactants of the reaction is about:2.___The enthalpy of the products of the reaction is about:3.___The activation energy of the reaction is about:4.___The heat of reaction (H) of the reaction is about:5.___The forward reaction is:6.___Addition of a catalyst would lower the:7.___The enthalpy of the reactants is _______than the enthalpy of the productsa. greaterb. kinetic energyc. 200 kJd. 120 kJe. exothermicf. endothermic.g. 80 kJh. 160 kJI. enthalpyj. activation energyk. less PLEASE HELP ASAP!!!! Please answer these question(s)! It has to do with math statistics. I will give you brainliest and thanks! Please answer my other questions! Conclusions Reread lines 3451 of Allied with green. What point is the narrator making about developments? How to do 5 choose 3 on calculator? Tracy took a test and had 24 questions. She got 5/6 of the questions correct. How many questions did she answer correctly? Write an equation to model your work 9. Lisa bought h shares of Home Depot stock for x dollars per share. She sold all of theshares years later for y dollars per share. Express her capital gain algebraically. If an economy is operating at a point inside the PPF, Group of answer choices society is paying too much for wages unlimited resources must satisfy scarce desires there is a scarcity of human resources relative to human wants therefore society must have some mechanism for making choices the production decisions are made by the government some of the nation's resources are unemployed Read the sentence from paragraph 3 of Passage 1.I know how it will be, his sister had said when he was preparing to migrate to this rural retreat; you will bury yourself down there and not speak to a living soul, and your nerves will be worse than ever from moping. . . .The underlined figurative language in this sentence conveys the idea that ResponsesMr. Nuttel is likely to get sicker during his stay in the countryMr. Nuttel is likely to get sicker during his stay in the countrythe people Mr. Nuttels sister wants him to meet have diedthe people Mr. Nuttels sister wants him to meet have diedthe rural area Mr. Nuttel is visiting is sparsely populatedthe rural area Mr. Nuttel is visiting is sparsely populatedMr. Nuttels sister believes he will become isolatedMr. Nuttels sister believes he will become isolated Segment AB is tangent to c.find AB. write and informative essay on a greek god Find x.Round to the nearest tenth:28350 ftyx = [ ? ]ft The circumference of a circle can be represented by the equation C= 2r. Rewritethis equation to represent the value of r in terms of C and . Use your new equation to find the radius of a circle that has a circumference of 54 inches. Leave your answer in terms of pi and solve algebraically What neurons carry motor messages?A. UnipolarB. BipolarC.MultipolarD.Anaxonic Match the situation to the type of operating system installation best suited for it. 1 . Clean installation A new employee will be using a computer that has been in storage for some time. 2 . Upgrade installation The sales department is having all of its computers replaced. 3 . Multiboot installation A graphic artist has purchased high-end software to create animations. Boulder Company reports current E&P of $500,000 this year and accumulated negative E&P at the beginning of the year of $200,000. Boulder distributed $400,000 to its sole shareholder on December 31 of this year. How much of the distribution is treated as a dividend this year? Which of the following is part of the microenvironment of a firm's marketing environment? A) the political state of the country in which the firm exists what is 20x + 30x ( 23 - ( -9)