Question

(x-y)的立方-4（x-y)的平方+4（x-y)怎么算

Answer 1

(x-y)的立方-4（x-y)的平方+4（x-y)

= (x-y) { (x-y)的平方-4（x-y)+4}

= (x-y)(x-y-2)的平方