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This module is from Elementary Algebra</link>by Denny Burzynski and Wade Ellis, Jr. Methods of solving quadratic equations as well as the logic underlying each method are discussed. Factoring, extraction of roots, completing the square, and the quadratic formula are carefully developed. The zero-factor property of real numbers is reintroduced. The chapter also includes graphs of quadratic equations based on the standard parabola, y = x^2, and applied problems from the areas of manufacturing, population, physics, geometry, mathematics (numbers and volumes), and astronomy, which are solved using the five-step method.This module contains an exercise supplement for the chapter "Quadratic Equations".

Exercise supplement

Solving quadratic equations ( [link] ) - solving quadratic equations by factoring ( [link] )

For the following problems, solve the equations.

( x 2 ) ( x 5 ) = 0

x = 2 , 5

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( b + 1 ) ( b 6 ) = 0

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( a + 10 ) ( a 5 ) = 0

a = 10 , 5

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( y 3 ) ( y 4 ) = 0

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( m 8 ) ( m + 1 ) = 0

m = 8 , 1

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( 4 y + 1 ) ( 2 y + 3 ) = 0

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( x + 2 ) ( 3 x 1 ) = 0

x = 2 , 1 3

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( 5 a 2 ) ( 3 a 10 ) = 0

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x ( 2 x + 3 ) = 0

x = 0 , 3 2

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( y + 3 ) 2 = 0

y = 3

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16 y 2 49 = 0

y = ± 7 4

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a 2 + 6 a + 8 = 0

a = 4 , 2

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s 2 9 s + 8 = 0

s = 1 , 8

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11 y 2 = 6 y 2

y = 1 6 , 2

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3 ( y 2 8 ) = 7 y

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a ( 4 b + 7 ) = 0

a = 0 ; b = 7 4

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5 a 2 125 = 0

a = ± 5

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m 2 6 m + 5 = 0

m = 5 , 1

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x 2 + 3 x = 28

x = 7 , 4

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2 y 2 6 y = 8

y = 4 , 1

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2 r 2 = 5 3 r

r = 5 2 , 1

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Solving quadratic equations using the method of extraction of roots ( [link] )

For the following problems, solve the equations using extraction of roots.

s 2 10 = 0

s = ± 10

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3 y 2 = 75

y = ± 5

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Solve y 2 = 4 a 2 for y .

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Solve m 2 = 16 n 2 p 4 for m .

m = ± 4 n p 2

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Solve x 2 = 25 y 4 z 10 w 8 for x .

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Solve x 2 y 2 = 0 for y .

y = ± x

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Solve a 4 b 8 x 6 y 12 z 2 = 0 for a 2 .

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( x 2 ) 2 = 9

x = 5 , 1

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( a + 10 ) 2 = 1

a = 11 , 9

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( r 8 ) 2 = 10

r = 8 ± 10

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( a 2 ) 2 = 2

No real number solution.

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Solve ( x 2 b ) 2 = b 2 for x

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Solve ( y + 6 ) 2 = a for y .

y = 6 ± a

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Solve ( 2 a 5 ) 2 = c for a .

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Solve ( 3 m 11 ) 2 = 2 a 2 for m .

m = 11 ± a 2 3

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Solving quadratic equations using the method of completing the square ( [link] ) - solving quadratic equations using the quadratic formula ( [link] )

For the following problems, solve the equations by completing the square or by using the quadratic formula.

s 2 + 2 s 24 = 0

s = 4 , 6

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b 2 + b 8 = 0

b = 1 ± 33 2

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5 a 2 + 2 a 6 = 0

a = 1 ± 31 5

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y 2 = 2 y + 1

y = 1 ± 2

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r 2 + 2 r = 9

r = 1 ± 10

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10 x 3 + 2 x 2 22 x = 0

x = 0 , 1 ± 221 10

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6 r 3 + 6 r 2 3 r = 0

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15 x 2 + 2 x 3 = 12 x 4

x = 0 , 1 ± 181 12

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6 x 3 6 x = 6 x 2

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( x + 3 ) ( x 4 ) = 3

x = 1 ± 61 2

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( y 1 ) ( y 2 ) = 6

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( a + 3 ) ( a + 4 ) = 10

No real number solution.

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( 2 m + 1 ) ( 3 m 1 ) = 2

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( 5 r + 6 ) ( r 1 ) = 2

r = 1 ± 161 10

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4 x 2 + 2 x 3 = 3 x 2 + x + 1

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5 a 2 + 5 a + 4 = 3 a 2 + 2 a + 5

a = 3 ± 17 4

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( r 8 ) 2 = 70

r = 8 ± 70

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Applications ( [link] )

For the following problems, find the solution.

The revenue R , in dollars, collected by a certain manufacturer of inner tubes is related to the number x of inner tubes sold by R = 1400 16 x + 3 x 2 . How many inner tubes must be sold to produce a profit of $1361?

No solution.

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A study of the air quality in a particular city by an environmental group suggests that t years from now the level of carbon monoxide, in parts per million, in the air will be A = 0.8 t 2 + 0.5 t + 3.3.
(a) What is the level, in parts per million, of carbon monoxide in the air now?
(b) How many years from now will the carbon monoxide level be at 6 parts per million?

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A contractor is to pour a concrete walkway around a community garden that is 15 feet wide and 50 feet long. The area of the walkway and garden is to be 924 square feet and of uniform width. How wide should the contractor make it?

x 1.29 feet

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A ball thrown vertically into the air has the equation of motion h = 144 + 48 t 16 t 2
(a) How high is the ball at t = 0 ?
(b) How high is the ball at t = 1 ?
(c) When does the ball hit the ground?

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The length of a rectangle is 5 feet longer than three times its width. Find the dimensions if the area is to be 138 square feet.

w = 6

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The area of a triangle is 28 square centimeters. The base is 3 cm longer than the height. Find both the length of the base and the height.

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The product of two consecutive integers is 210. Find them.

x = 15 , 14 , or 14 , 15

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The product of two consecutive negative integers is 272. Find them.

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A box with no top and a square base is to be made by cutting out 3-inch squares from each corner and folding up the sides of a piece of cardboard. The volume of the box is to be 25 cubic inches. What size should the piece of cardboard be?

x = 18 + 5 3 3

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Questions & Answers

A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
Aislinn Reply
cm
tijani
what is titration
John Reply
what is physics
Siyaka Reply
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Jude Reply
Can you compute that for me. Ty
Jude
what is the dimension formula of energy?
David Reply
what is viscosity?
David
what is inorganic
emma Reply
what is chemistry
Youesf Reply
what is inorganic
emma
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
Krampah Reply
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
Sahid Reply
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
Samuel Reply
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Joseph Reply
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
Ryan
what's motion
Maurice Reply
what are the types of wave
Maurice
answer
Magreth
progressive wave
Magreth
hello friend how are you
Muhammad Reply
fine, how about you?
Mohammed
hi
Mujahid
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
yasuo Reply
Who can show me the full solution in this problem?
Reofrir Reply
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Source:  OpenStax, Elementary algebra. OpenStax CNX. May 08, 2009 Download for free at http://cnx.org/content/col10614/1.3
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