作业帮9(x+2y)^2-4(x-2Y)^2
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9(x+2y)^2-4(x-2Y)^2
9(x+2y)^2-4(x-2Y)^2
9(x+2y)^2-4(x-2Y)^2
9(x+2y)^2-4(x-2Y)^2
=[3(x+2y)]^2-[2(x-2Y)]^2
=[3(x+2y)+2(x-2Y)][3(x+2y)-2(x-2Y)]
=(5x+2y)(x+10y)
9(x+2y)^2-4(x-2Y)^2
=3^2(x+2y)^2-2^2(x-2y)^2
=[3(x+2y)]^2-[2(x-2y)]^2
=[3(x+2y)+2(x-2y)][3(x+2y)+2(x-2y)]
=(5x+2y)(x+10y)