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Lesson 4.5, For use with pages 266-271 Find the exact value. ANSWER 7 ANSWER –12 1. √49 2. –√144

Lesson 4.5 , For use with pages 266-271

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1. √49. 2. –√144. Lesson 4.5 , For use with pages 266-271. Find the exact value. 7. ANSWER. –12. ANSWER. 82. 3. Use calculator to approximate the value of to the nearest tenth. 16. 1. - PowerPoint PPT Presentation

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Page 1: Lesson  4.5 , For use with pages  266-271

Lesson 4.5, For use with pages 266-271

Find the exact value.

ANSWER 7

ANSWER –12

1. √49

2. –√144

Page 2: Lesson  4.5 , For use with pages  266-271

Lesson 4.5, For use with pages 266-271

ANSWER 2.3

ANSWER 11 ft

4. The area of half of a square mural is 60 square feet. What is the length of a side of the mural?

12

163. Use calculator to approximate the value of

to the nearest tenth.

82

Page 3: Lesson  4.5 , For use with pages  266-271

4.5 Properties of Square Roots

Page 4: Lesson  4.5 , For use with pages  266-271

EXAMPLE 1 Use properties of square roots

Simplify the expression.

5= 4a.

80 516=

= 3 14b.

6 21 126= 9 14=

c.

4

81=

4

81=

2 9

d.

7

16=

7

16=

4

7

Page 5: Lesson  4.5 , For use with pages  266-271

GUIDED PRACTICEGUIDED PRACTICE for Example 1

271.

3= 327 39=

SOLUTION

982.

2= 798 249=

SOLUTION

Page 6: Lesson  4.5 , For use with pages  266-271

GUIDED PRACTICEGUIDED PRACTICE for Example 1

3.

6= 5

SOLUTION

SOLUTION

10 15

10 15 625150 ==

4. 8 28

14= 41416=224= 8 28

Page 7: Lesson  4.5 , For use with pages  266-271

GUIDED PRACTICEGUIDED PRACTICE for Example 1

5.

SOLUTION

SOLUTION

9

64=

3 8

9

64

9

64=

6. 15

4

15

4

15

4= =

15

2

Page 8: Lesson  4.5 , For use with pages  266-271

GUIDED PRACTICEGUIDED PRACTICE for Example 1

7.

SOLUTION

SOLUTION

11

25

11

25

11

25=

8. 36

49

36

4936

49=

= 5

11

76

=

Page 9: Lesson  4.5 , For use with pages  266-271

EXAMPLE 2 Rationalize denominators of fractions.

Simplify (a) 5

2and 3

7 + 2

SOLUTION

(a) 5

2

2

10=

=5

2

=5

2

2

2

(b)

Page 10: Lesson  4.5 , For use with pages  266-271

EXAMPLE 2 Rationalize denominators of fractions.

SOLUTION

(b)3

7 + 2=

3

7 + 2 7 – 2

7 – 2

=21 – 3 2

49 – 7 + 7 – 2 2 2

=21 – 3 2

47

Page 11: Lesson  4.5 , For use with pages  266-271

EXAMPLE 3 Solve a quadratic equation

Solve 3x2 + 5 = 41.

3x2 + 5 = 41 Write original equation.

3x2 = 36 Subtract 5 from each side.

x2 = 12 Divide each side by 3.

x = + 12 Take square roots of each side.

x = + 4 3

x = + 2 3

Product property

Simplify.

Page 12: Lesson  4.5 , For use with pages  266-271

EXAMPLE 3 Solve a quadratic equation

ANSWER

The solutions are and 2 3 2 3–

Check the solutions by substituting them into the original equation.

3x2 + 5 = 41

3( )2 + 5 = 41 ?2 3

41 = 41

3(12) + 5 = 41 ?

3x2 + 5 = 41

3( )2 + 5 = 41 ? – 2 3

41 = 41

3(12) + 5 = 41 ?

Page 13: Lesson  4.5 , For use with pages  266-271

EXAMPLE 4 Standardized Test Practice

SOLUTION

15 (z + 3)2 = 7 Write original equation.

(z + 3)2 = 35 Multiply each side by 5.

z + 3 = + 35 Take square roots of each side.

z = – 3 + 35 Subtract 3 from each side.

The solutions are – 3 + and – 3 – 35 35

Page 14: Lesson  4.5 , For use with pages  266-271

EXAMPLE 4 Standardized Test Practice

ANSWER

The correct answer is C.

Page 15: Lesson  4.5 , For use with pages  266-271

GUIDED PRACTICE for Examples 2, 3, and 4GUIDED PRACTICE

Simplify the expression.

9.

SOLUTION

6

5

5

30=

=6

5

=6

5

5

5

6

5

Page 16: Lesson  4.5 , For use with pages  266-271

GUIDED PRACTICE for Examples 2, 3, and 4GUIDED PRACTICE

Simplify the expression.

10.

SOLUTION

9

8=

9

8

=9

8

8

8

9

8

2

4=

3

Page 17: Lesson  4.5 , For use with pages  266-271

GUIDED PRACTICE for Examples 2, 3, and 4GUIDED PRACTICE

Simplify the expression.

11.

SOLUTION

17

12=

17

12

=17

12

12

12

17

12

51

12=

2 51

6=

Page 18: Lesson  4.5 , For use with pages  266-271

GUIDED PRACTICE for Examples 2, 3, and 4GUIDED PRACTICE

Simplify the expression.

12.

SOLUTION

19

21

399

21=

=19

21

=19

21

21

21

19

21

Page 19: Lesson  4.5 , For use with pages  266-271

SOLUTION

– 6

7 – 5=

– 6

7 – 5 7 + 5

7 + 5

=– 42 – 6 5

49 – 7 + 7 – 5 5 5

=– 21 – 3 5

22

for Examples 2, 3, and 4GUIDED PRACTICE

13. – 6

7 – 5

Page 20: Lesson  4.5 , For use with pages  266-271

SOLUTION

2

4 + 11=

2

4 + 11 4 – 11

4 – 11

=8 – 2 11

16 – 4 + 4 – 1111 11

=8 – 2 11

5

for Examples 2, 3, and 4GUIDED PRACTICE

14. 2

4 + 11

Page 21: Lesson  4.5 , For use with pages  266-271

SOLUTION

– 1

9 + 7=

– 1

9 + 7 9 – 7

9 – 7

=– 9 + 7

81 – 9 + 9 – 77 7

=– 9 + 7

74

for Examples 2, 3, and 4GUIDED PRACTICE

15. – 1

9 + 7

Page 22: Lesson  4.5 , For use with pages  266-271

SOLUTION

4

8 – 3=

4

8 – 3 8 + 3

8 + 3

=32 + 4 3

64 – 4 + 4 – 3 3 3

=32 + 4 3

61

for Examples 2, 3, and 4GUIDED PRACTICE

16. 4

8 – 3

Page 23: Lesson  4.5 , For use with pages  266-271

SOLUTION

for Examples 2, 3, and 4GUIDED PRACTICE

17.

Solve the equation.

5x2 = 80

Write original equation.5x2 = 80

x2 = 16 Divide each side by 5.

x = + 16 Take square roots of each side.

x = + 4 4

x = + 4

Product property

Simplify.

Page 24: Lesson  4.5 , For use with pages  266-271

for Examples 2, 3, and 4GUIDED PRACTICE

ANSWER

The solutions are and . 4 4–

Check Check the solutions by substituting them into the original equation.

5x2 = 80

5(– 4)2 = 80 ?

80 = 80

5(16) = 80?

5x2 = 80

80 = 80

5(16) = 80?

5(4)2 = 80 ?

Page 25: Lesson  4.5 , For use with pages  266-271

SOLUTION

for Examples 2, 3, and 4GUIDED PRACTICE

18.

Solve the equation.

z2 – 7 = 29

Write original equation.

z2 = 36

z = + 36 Take square roots of each side.

z = + 6 6

z = + 6

Product property

Simplify.

z2 – 7 = 29

Add 7 to each side.

Page 26: Lesson  4.5 , For use with pages  266-271

for Examples 2, 3, and 4GUIDED PRACTICE

ANSWER

The solutions are and . 6 6–

Check the solutions by substituting them into the original equation.

29 = 29

z2 – 7 = 29

(6)2 – 7 = 29 ?

?36 – 7 = 2929 = 29

z2 – 7 = 29

(– 6)2 – 7 = 29 ?

36 – 7 = 29 ?

Page 27: Lesson  4.5 , For use with pages  266-271

SOLUTION

for Examples 2, 3, and 4GUIDED PRACTICE

19.

Write original equation.

Take square roots of each side.

Division property

3(x – 2)2 = 40

3(x – 2)2 = 40

Divide each side by 3.(x – 2)2 =403

+(x – 2) =403

x =40

32 +

x =40

32 + 3

3

=120

32 +

Page 28: Lesson  4.5 , For use with pages  266-271

for Examples 2, 3, and 4GUIDED PRACTICE

=4(30)

32 +

= 2 30

32 +

ANSWER

The solutions are . 2 30

32 +

Page 29: Lesson  4.5 , For use with pages  266-271

EXAMPLE 5 Model a dropped object with a quadratic function

Science Competition

For a science competition, students must design a container that prevents an egg from breaking when dropped from a height of 50 feet. How long does the container take to hit the ground ?

Page 30: Lesson  4.5 , For use with pages  266-271

EXAMPLE 5 Model a dropped object with a quadratic function

SOLUTION

h = – 16t 2 + h0 Write height function. 0 = – 16t 2 + 50 Substitute 0 for h and 50 for h0.

– 50 = – 16t 2 Subtract 50 from each side.5016 = t2 Divide each side by – 16.

50

16+ = t2 Take square roots of each side.

+ 1.8 t Use a calculator.

Page 31: Lesson  4.5 , For use with pages  266-271

EXAMPLE 5 Model a dropped object with a quadratic function

ANSWER

Reject the negative solution, – 1.8 , because time must be positive. The container will fall for about 1.8 seconds before it hits the ground.

Page 32: Lesson  4.5 , For use with pages  266-271

GUIDED PRACTICE for Example 5GUIDED PRACTICE

What If? In Example 5, suppose the egg container is dropped from a height of 30 feet. How long does the container take to hit the ground?

20.

SOLUTION

h = – 16t 2 + h0 Write height function. 0 = – 16t 2 + 30 Substitute 0 for h and 30 for h0.

– 30 = – 16t 2 Subtract 30 from each side.3016 = t2 Divide each side by – 16.

30

16+ = t2 Take square roots of each side.

+ 1.4 t Use a calculator.

Page 33: Lesson  4.5 , For use with pages  266-271

GUIDED PRACTICE for Example 5GUIDED PRACTICE

ANSWER

Reject the negative solution, – 1.4, because time must be positive. The container will fall for about 1.4 seconds before it hits the ground.