Solve x2 = 12x – 15 by completing the square. which is the solution set of the equation? -square root of 51,-6+ square root of 51) - square root of 21,-6+ square root of 21) - square root of 51, 6+ square root of 51) - square root of 21, 6 + square root of 21) i will mark brainliest for the correct answer