Solve 3x^2 + 18x + 15 = 0 by completing the square.
a: 3(x + 3)^2 = 6; x = −3 + √2, x = −3 − √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 + √76, x = −9 − √76

my math:
3x^2 + 18x + 15 = 0
3(x^2 + 18x + ) + 15 = 0
3(x^2 + 18x + 81) + 15 - 81 = 0
(x^2 + 18x + 81) - 228 = 0

what do i do now? can someone me ?