(x-y)²-2y(x+y)怎么化简

问题描述:

(x-y)²-2y(x+y)怎么化简

(x-y)²-2y(x+y)=x²-2xy+y²-2xy-2y²=x²-4xy-y²=x²-4xy+4y²-5y²=(x-2y)²-5y²=(x-2y+根5)*(x-2y-根5)