1, -2(a-b)(x-y)^22, (y-1)(x+1)(x-1)3 -3x^3(x+2)^2(x-2)^2
2(B-A)(X-Y)^2(Y-1)(X+1)(X-1)-3(X^3)×(X+2)^2×(X-2)^2
