Solve x2 + 6x = 9 for x by completing the square.
a. x = −6
b. x = 0
c. x equals plus or minus square root of 18 minus 3
d. x = x equals plus or minus square root of 18 plus 3

c. x equals plus or minus square root of 18 minus 3

Step-by-step explanation:

1. x^2+6x+(6/2)^2=9+(6/2)^2

2. (x+6/2)^2=18

3. (x+3)^2=18

x= plus or minus root 18 minus 3

Simplified would be x plus or minus 3 root 2 minus 3

a. she will receive a refund of $278.

step-by-step explanation: