By inspection, 4 (x - y)3 + 6 (x - y)2 gives
2(x + y) (2x - 3 + 2y)
2(x + y)2 (2x + 3y - 3)
2(x - y)2 (2x - 2y + 6)
2(x - y)2 (2x - 2y + 3)
4(x - y)3 + 6 (x - y)2 = 2(x - y)2 [2(x - y) + 3]
= 2(x - y)2 (2x - 2y + 3)
By inspection, 9 (2a - 3b)2 - 12 (2a - 3b) gives
By inspection, a3 - 2a2 + a - 2 gives