<< Chapter < Page Chapter >> Page >

In the previous set of exercises, you worked with the quadratic equation R = x 2 + 100 x that modeled the revenue received from selling backpacks at a price of x dollars. You found the selling price that would give the maximum revenue and calculated the maximum revenue. Now you will look at more characteristics of this model.
Graph the equation R = x 2 + 100 x . Find the values of the x -intercepts.

Got questions? Get instant answers now!

Writing exercises

For the revenue model in [link] and [link] , explain what the x -intercepts mean to the computer store owner.

Answers will vary.

Got questions? Get instant answers now!

For the revenue model in [link] and [link] , explain what the x -intercepts mean to the backpack retailer.

Got questions? Get instant answers now!

Self check

After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.

This table has six rows and four columns. The first row is a header row and it labels each column. The first column is labeled

What does this checklist tell you about your mastery of this section? What steps will you take to improve?

10.1 Solve Quadratic Equations Using the Square Root Property

In the following exercises, solve using the Square Root Property.

m 2 40 = 0

m = ± 2 10

Got questions? Get instant answers now!

r 2 + 32 = 0

no solution

Got questions? Get instant answers now!

4 3 v 2 + 4 = 28

v = ± 3 2

Got questions? Get instant answers now!

5 c 2 + 3 = 19

c = ± 4 5 5

Got questions? Get instant answers now!

In the following exercises, solve using the Square Root Property.

( p 5 ) 2 + 3 = 19

p = 1 , 9

Got questions? Get instant answers now!

( u + 1 ) 2 = 45

u = −1 ± 3 5

Got questions? Get instant answers now!

( x 1 4 ) 2 = 3 16

x = 1 4 ± 3 4

Got questions? Get instant answers now!

( m 7 ) 2 + 6 = 30

m = 7 ± 2 6

Got questions? Get instant answers now!

( n 4 ) 2 50 = 150

Got questions? Get instant answers now!

( 5 c + 3 ) 2 = −20

no solution

Got questions? Get instant answers now!

m 2 6 m + 9 = 48

m = 3 ± 4 3

Got questions? Get instant answers now!

64 a 2 + 48 a + 9 = 81

a = 3 2 , 3 4

Got questions? Get instant answers now!

4 b 2 28 b + 49 = 25

Got questions? Get instant answers now!

10.2 Solve Quadratic Equations Using Completing the Square

In the following exercises, complete the square to make a perfect square trinomial. Then write the result as a binomial squared.

m 2 8 m

( m 4 ) 2

Got questions? Get instant answers now!

a 2 3 a

( a 3 2 ) 2

Got questions? Get instant answers now!

p 2 + 4 5 p

( p + 2 5 ) 2

Got questions? Get instant answers now!

In the following exercises, solve by completing the square.

c 2 + 20 c = 21

c = 1 , −21

Got questions? Get instant answers now!

x 2 4 x = 32

x = −4 , 8

Got questions? Get instant answers now!

r 2 + 6 r = −100

no solution

Got questions? Get instant answers now!

v 2 14 v = −31

v = 7 ± 3 2

Got questions? Get instant answers now!

m 2 + 10 m 4 = −13

m = −9 , −1

Got questions? Get instant answers now!

a 2 = 3 a + 8

a = 3 2 ± 41 2

Got questions? Get instant answers now!

( u + 8 ) ( u + 4 ) = 14

u = −6 ± 2 2

Got questions? Get instant answers now!

( z 10 ) ( z + 2 ) = 28

Got questions? Get instant answers now!

3 p 2 18 p + 15 = 15

p = 0 , 6

Got questions? Get instant answers now!

4 y 2 6 y = 4

y = 1 2 , 2

Got questions? Get instant answers now!

3 c 2 + 2 c = 9

c = 1 3 ± 2 7 3

Got questions? Get instant answers now!

10.3 Solve Quadratic Equations Using the Quadratic Formula

In the following exercises, solve by using the Quadratic Formula.

4 x 2 5 x + 1 = 0

x = 1 4 , 1

Got questions? Get instant answers now!

r 2 r 42 = 0

r = −6 , 7

Got questions? Get instant answers now!

4 v 2 + v 5 = 0

v = 5 4 , 1

Got questions? Get instant answers now!

3 m 2 + 8 m + 2 = 0

m = −4 ± 10 3

Got questions? Get instant answers now!

6 a 2 5 a + 2 = 0

no real solution

Got questions? Get instant answers now!

u ( u 10 ) + 3 = 0

u = 5 ± 22

Got questions? Get instant answers now!

1 8 p 2 1 5 p = 1 20

p = 4 ± 6 5

Got questions? Get instant answers now!

4 c 2 + 4 c + 1 = 0

c = 1 2

Got questions? Get instant answers now!

In the following exercises, determine the number of solutions to each quadratic equation.

  1. 9 x 2 6 x + 1 = 0
  2. 3 y 2 8 y + 1 = 0
  3. 7 m 2 + 12 m + 4 = 0
  4. 5 n 2 n + 1 = 0

1 2 2 none

Got questions? Get instant answers now!
  1. 5 x 2 7 x 8 = 0
  2. 7 x 2 10 x + 5 = 0
  3. 25 x 2 90 x + 81 = 0
  4. 15 x 2 8 x + 4 = 0
Got questions? Get instant answers now!

In the following exercises, identify the most appropriate method (Factoring, Square Root, or Quadratic Formula) to use to solve each quadratic equation.

  1. 16 r 2 8 r + 1 = 0
  2. 5 t 2 8 t + 3 = 9
  3. 3 ( c + 2 ) 2 = 15

factor Quadratic Formula square root

Got questions? Get instant answers now!
  1. 4 d 2 + 10 d 5 = 21
  2. 25 x 2 60 x + 36 = 0
  3. 6 ( 5 v 7 ) 2 = 150
Got questions? Get instant answers now!

10.4 Solve Applications Modeled by Quadratic Equations

In the following exercises, solve by using methods of factoring, the square root principle, or the quadratic formula.

Find two consecutive odd numbers whose product is 323.

Two consecutive odd numbers whose product is 323 are 17 and 19, and −17 and −19 .

Got questions? Get instant answers now!

Questions & Answers

if three forces F1.f2 .f3 act at a point on a Cartesian plane in the daigram .....so if the question says write down the x and y components ..... I really don't understand
Syamthanda Reply
hey , can you please explain oxidation reaction & redox ?
Boitumelo Reply
hey , can you please explain oxidation reaction and redox ?
Boitumelo
for grade 12 or grade 11?
Sibulele
the value of V1 and V2
Tumelo Reply
advantages of electrons in a circuit
Rethabile Reply
we're do you find electromagnetism past papers
Ntombifuthi
what a normal force
Tholulwazi Reply
it is the force or component of the force that the surface exert on an object incontact with it and which acts perpendicular to the surface
Sihle
what is physics?
Petrus Reply
what is the half reaction of Potassium and chlorine
Anna Reply
how to calculate coefficient of static friction
Lisa Reply
how to calculate static friction
Lisa
How to calculate a current
Tumelo
how to calculate the magnitude of horizontal component of the applied force
Mogano
How to calculate force
Monambi
a structure of a thermocouple used to measure inner temperature
Anna Reply
a fixed gas of a mass is held at standard pressure temperature of 15 degrees Celsius .Calculate the temperature of the gas in Celsius if the pressure is changed to 2×10 to the power 4
Amahle Reply
How is energy being used in bonding?
Raymond Reply
what is acceleration
Syamthanda Reply
a rate of change in velocity of an object whith respect to time
Khuthadzo
how can we find the moment of torque of a circular object
Kidist
Acceleration is a rate of change in velocity.
Justice
t =r×f
Khuthadzo
how to calculate tension by substitution
Precious Reply
hi
Shongi
hi
Leago
use fnet method. how many obects are being calculated ?
Khuthadzo
khuthadzo hii
Hulisani
how to calculate acceleration and tension force
Lungile Reply
you use Fnet equals ma , newtoms second law formula
Masego
please help me with vectors in two dimensions
Mulaudzi Reply
how to calculate normal force
Mulaudzi
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply
Practice Key Terms 6

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Elementary algebra. OpenStax CNX. Jan 18, 2017 Download for free at http://cnx.org/content/col12116/1.2
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Elementary algebra' conversation and receive update notifications?

Ask