Name ______Date ______

LESSON 4.7

Practice B

For use with pages 283-291

Solve the equation by finding square roots.

1.x2 + 8x+16 = 9

2.x26x + 9 = 25

3.x2 12x + 36 = 49

4.2x2 12x + 18 = 32

5.4x2 4x + 1 = 36

6.5x2 20x + 20 = 35

7.x2x += 1

8.x2 +x += 3

9.9x2 + 12x + 4 = 5

Find the value of c that makes the expression a perfect square trinomial.

Then write the expression as a square of a binomial.

10.x2 + 8x + c

11.x2 22x + c

12.x2 + 16x + c

13.x2 + 3x + c

14.x2  9x + c

15.9x2 12x + c

Solve the equation by completing the square.

16.x2 + 4x = 1

17.x210x= 10

18.x2 2x 9 = 0

19.x2 + 6x + 10 = 0

20.x2 + 8x + 4 = 0

21.3x2 + 36x = 42

22.x224x+81 = 0

23.4x2 + 20x + 25 = 0

24.3x2 3x + 9 = 0

25.6x2 12x 18 = 0

Write the quadratic function in vertex form. Then identify the vertex.

26.y=x2+14x+11

27.y = x2 8x + 10

28.y = 2x2 + 4x – 5

29.y = 3x2 9x + 18

Find the value of x.

30.Area of rectangle = 84

31.Area of triangle = 20

32.Shot Put In a track and field event, a contestant had a throw in the shot put that can be modeled by y =  0.02x2 + x + 6 where x is the shot put’s horizontal distance & (in feet) and y is the corresponding height (in feet). How long was the throw? Round the answer to the nearest tenth.