将(x-2y)(x-2y)(-x²＋3xy－2y²）化成完全平方形式.

题目

将(x-2y)(x-2y)(-x²＋3xy－2y²）化成完全平方形式.

答案

=-(x-y)(x-2y)(x2-3xy+2y2）=-(x-y)(x-2y)（x-y)(x-2y)=-(x-y)^2(x-2y)^2