因式分解9(x+2y)^2-25(x-2y)^2
问题描述：
因式分解9(x+2y)^2-25(x-2y)^2
答
9(x+2y)^2-25(x-2y)^2
=[3(x+2y)]^2-[5(x-2y)]^2
=[3(x+2y)+5(x-2y)][3(x+2y)-5(x-2y)]
=(8x-4y)(-2x+16y)
=8(2x-y)(-x+8y)
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