x^2(x-y)+(y-x),9(3x-2y)^2-(x-y)^2,(x-2)^2+x-4,a^2-4a-b^2+4,a^2b^2+4ab+4-b^2

题目

x^2(x-y)+(y-x),9(3x-2y)^2-(x-y)^2,(x-2)^2+x-4,a^2-4a-b^2+4,a^2b^2+4ab+4-b^2
麻烦速度

答案

是因式分解吧
x^2(x-y)+(y-x)=(x-y)(x^2-1)=(x-y)(x+1)(x-1)
9(3x-2y)^2-(x-y)^2=(9x-6y)^2-(x-y)^2=(9x-6y+x-y)(9x-6y-x+y)=(10x-7y)(8x-5y)
(x-2)^2+x-4=x^2-4x+4+x-4=x^2-3x=x(x-3)
a^2-4a-b^2+4=(a+2)^2-b^2=(a+b+2)(a-b+2)
a^2b^2+4ab+4-b^2=(ab+2)^2-b^2=(ab+b+2)(ab-b+2)