9(x-y)^2-6(y-x)^2+1是9(x-y)^2-6(y-x)+1 打错了
问题描述：
9(x-y)^2-6(y-x)^2+1
是9(x-y)^2-6(y-x)+1 打错了
答
9(x-y)²-6（y-x）+1
=[3(x-y)]²+6(x-y)+1
=[3(x-y)+1]²
=[3x-3y+1]²
答
中间提取一个负号
9(x-y)^2-6(y-x)^2+1
=9(x-y)^2+6(x-y)^2+1
=[3(x-y)+1]^2
(3x-3y+1)^2
答
9(x-y)^2-6(y-x)+1
=9(x-y)^2+6(x-y)+1
=[3(x-y)+1]^2
=(3x-3y+1)^2
答
原式=9(y-x)^2-6(y-x)+1
=[3(y-x)-1]^2（完全平方公式）
=(3y-3x-1)^2