因式分解：（步骤）4+12（x-y）+9（x-y）平方=谢谢4+12（x-y）+9（x-y）^2=[3(x-y)]^2+

4+12（x-y）+9（x-y）^2
=[3(x-y)]^2+12(x-y)+2^2
=[3(x-y)+2]^2
=(3x-3y+2)^2

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4+12（x-y）+9（x-y）^2
=[3(x-y)]^2+12(x-y)+2^2
=[3(x-y)+2]^2
=(3x-3y+2)^2
这样可以么？

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