solve 3x2 18x 15 = 0 by completing the square.

a. 3(x 3)2 = 6; x = −3 square root 2, x = −3 − square root 2
b. 3(x 9)2 = 12; x = −11, x = −7
c. 3(x 3)2 = 12; x = −5, x = −1
d. 3(x 9)2 = 228; x = −9 square root 76, x = −9 − square root 76