Which number from the replacement set {6, 12, 24} is a solution for the equation 3x + 12 = 36 − x?

Anyone know? will mark brainliest if you're correct!

What statement is true? 2x^2-9x+2=-1

The diagonals of a quadrilaretral intersect at (-1,4). one of the sides of the quadrilateral is bounded by (2,7) and (-3,5) determine the coordinates of the other side in order for the quadrilaretral to be a square.