Which are steps that could be used to solve 0 = 9(x2 + 6x) – 18 by completing the square? Check all that apply.18 + 81 = 9(x2 + 6x + 9)18 + 9 = 9(x2 + 6x + 9)18 + 36 = 9(x2 + 6x + 36)11 = (x + 3)2 StartRoot 342 EndRoot = (x + 6)2 StartRoot 99 EndRoot = (x + 3)2