<< Chapter < Page Chapter >> Page >

Solve: ( 3 r + 4 ) 2 = −8 .

no real solution

Got questions? Get instant answers now!

Solve: ( 2 t 8 ) 2 = −10 .

no real solution

Got questions? Get instant answers now!

The left sides of the equations in the next two examples do not seem to be of the form a ( x h ) 2 . But they are perfect square trinomials, so we will factor to put them in the form we need.

Solve: p 2 10 p + 25 = 18 .

Solution

The left side of the equation is a perfect square trinomial. We will factor it first.

p 2 10 p + 25 = 18 Factor the perfect square trinomial. ( p 5 ) 2 = 18 Use the Square Root Property. p 5 = ± 18 Simplify the radical. p 5 = ± 3 2 Solve for p . p = 5 ± 3 2 Rewrite to show two solutions. p = 5 + 3 2 , p = 5 3 2 Check. We leave the check for you.

Got questions? Get instant answers now!
Got questions? Get instant answers now!

Solve: x 2 6 x + 9 = 12 .

x = 3 + 2 3 , x = 3 2 3

Got questions? Get instant answers now!

Solve: y 2 + 12 y + 36 = 32 .

y = −6 + 4 2 , y = −6 4 2

Got questions? Get instant answers now!

Solve: 4 n 2 + 4 n + 1 = 16 .

Solution

Again, we notice the left side of the equation is a perfect square trinomial. We will factor it first.

4 n 2 + 4 n + 1 = 16
Factor the perfect square trinomial. ( 2 n + 1 ) 2 = 16
Use the Square Root Property. 2 n + 1 = ± 16
Simplify the radical. 2 n + 1 = ± 4
Solve for n . 2 n = 1 ± 4
Divide each side by 2. 2 n 2 = 1 ± 4 2 n = 1 ± 4 2
Rewrite to show two solutions. n = 1 + 4 2 , n = 1 4 2
Simplify each equation. n = 3 2 , n = 5 2
Check.
.
Got questions? Get instant answers now!
Got questions? Get instant answers now!

Solve: 9 m 2 12 m + 4 = 25 .

m = 7 , m = −3

Got questions? Get instant answers now!

Solve: 16 n 2 + 40 n + 25 = 4 .

n = 3 4 , n = 7 4

Got questions? Get instant answers now!

Access these online resources for additional instruction and practice with solving quadratic equations:

Key concepts

  • Square Root Property
    If x 2 = k , and k 0 , then x = k or x = k .

Practice makes perfect

Solve Quadratic Equations of the form a x 2 = k Using the Square Root Property

In the following exercises, solve the following quadratic equations.

r 2 24 = 0

r = ± 2 6

Got questions? Get instant answers now!

u 2 300 = 0

u = ± 10 3

Got questions? Get instant answers now!

x 2 + 20 = 0

no real solution

Got questions? Get instant answers now!

2 5 a 2 + 3 = 11

a = ± 2 5

Got questions? Get instant answers now!

7 p 2 + 10 = 26

p = ± 4 7 7

Got questions? Get instant answers now!

Solve Quadratic Equations of the Form a ( x h ) 2 = k Using the Square Root Property

In the following exercises, solve the following quadratic equations.

( x + 2 ) 2 = 9

x = 1 , x = −5

Got questions? Get instant answers now!

( u 6 ) 2 = 64

u = 14 , u = −2

Got questions? Get instant answers now!

( m 6 ) 2 = 20

m = 6 ± 2 5

Got questions? Get instant answers now!

( r 1 2 ) 2 = 3 4

r = 1 2 ± 3 2

Got questions? Get instant answers now!

( a 7 ) 2 + 5 = 55

a = 7 ± 5 2

Got questions? Get instant answers now!

( b 1 ) 2 9 = 39

Got questions? Get instant answers now!

( 5 c + 1 ) 2 = −27

no real solution

Got questions? Get instant answers now!

m 2 4 m + 4 = 8

m = 2 ± 2 2

Got questions? Get instant answers now!

25 x 2 30 x + 9 = 36

x = 3 5 , x = 9 5

Got questions? Get instant answers now!

Mixed Practice

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

( a 4 ) 2 = 28

a = 4 ± 2 7

Got questions? Get instant answers now!

9 w 2 24 w + 16 = 1

w = 1 , w = 5 3

Got questions? Get instant answers now!

a 2 18 = 0

a = ± 3 2

Got questions? Get instant answers now!

( p 1 3 ) 2 = 7 9

p = 1 3 ± 7 3

Got questions? Get instant answers now!

m 2 + 12 = 0

no real solution

Got questions? Get instant answers now!

u 2 14 u + 49 = 72

u = 7 ± 6 2

Got questions? Get instant answers now!

( m 4 ) 2 + 3 = 15

m = 4 ± 2 3

Got questions? Get instant answers now!

( n 7 ) 2 8 = 64

Got questions? Get instant answers now!

( x + 5 ) 2 = 4

x = −3 , x = −7

Got questions? Get instant answers now!

6 c 2 + 4 = 29

c = ± 5 6 6

Got questions? Get instant answers now!

( x 6 ) 2 + 7 = 3

no real solution

Got questions? Get instant answers now!

Everyday math

Paola has enough mulch to cover 48 square feet. She wants to use it to make three square vegetable gardens of equal sizes. Solve the equation 3 s 2 = 48 to find s , the length of each garden side.

4 feet

Got questions? Get instant answers now!

Kathy is drawing up the blueprints for a house she is designing. She wants to have four square windows of equal size in the living room, with a total area of 64 square feet. Solve the equation 4 s 2 = 64 to find s , the length of the sides of the windows.

Got questions? Get instant answers now!

Writing exercises

Explain why the equation x 2 + 12 = 8 has no solution.

Answers will vary.

Got questions? Get instant answers now!

Explain why the equation y 2 + 8 = 12 has two solutions.

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 three rows and four columns. The first row is a header row and it labels each column. The first column is labeled “I can …”, the second “Confidently”, the third “With some help” and the last “No–I don’t get it”. In the “I can…” column the next row reads “solve quadratic equations of the form a x squared equals k using the square root property.” and the last row reads “solve quadratic equations of the form a times the quantity x minus h squared equals k using the square root property.” The remaining columns are blank.

If most of your checks were:

…confidently: Congratulations! You have achieved the objectives in this section. Reflect on the study skills you used so that you can continue to use them. What did you do to become confident of your ability to do these things? Be specific.

…with some help: This must be addressed quickly because topics you do not master become potholes in your road to success. In math, every topic builds upon previous work. It is important to make sure you have a strong foundation before you move on. Who can you ask for help? Your fellow classmates and instructor are good resources. Is there a place on campus where math tutors are available? Can your study skills be improved?

…no-I don’t get it! This is a warning sign and you must not ignore it. You should get help right away or you will quickly be overwhelmed. See your instructor as soon as you can to discuss your situation. Together you can come up with a plan to get you the help you need.

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 2

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