First simplify, then evaluate: [(X-Y) 2 + (X-Y) (x + y)] x, where x = - 1, y = 12

First simplify, then evaluate: [(X-Y) 2 + (X-Y) (x + y)] x, where x = - 1, y = 12

[(X-Y) 2 + (X-Y) (x + y)] / x, = (x2-2xy + Y2 + x2-y2) / x, = (2x2-2xy) / x, = 2x-2y, when x = - 1, y = 12, the original formula = 2 × (- 1) - 2 × 12 = - 3