因式分解:1.(m-n)²-2m+2n 2.x²-y²-(x+y)²

问题描述:

因式分解:1.(m-n)²-2m+2n 2.x²-y²-(x+y)²


(m-n)²-2m+2n
=(m-n)²-2(m-n)
=(m-n)(m-n-2)
=(x-y)(x+y)-(x+y)²
=(x+y)(x-y-x-y)
=-2y(x+y)