4(X+2Y)^2-9(X-Y)^2

4(X+2Y)^2-9(X-Y)^2
4(X+2Y)^2-9(X-Y)^2

4(X+2Y)^2-9(X-Y)^2
你是说分解因式吧,
=[2(x+2y)]^2-[3(x-y)]^2
=(2x+4y)^2-(3x-3y)^2
=[(2x+4y)+(3x-3y)][(2x+4y)-(3x-3y)]
=(5x+y)(-x+7y)

4(X+2Y)^2-9(X-Y)^2
=4X²+16Y²+16XY-9X²-9Y²+18XY
=-5X²+7Y²+34XY

分解因式为：
原式=[2²(x+2y)²]-[3²(x-y)²]
=[2(x+2y)]²-[3(x-y)]²
=[2(x+2y)+3(x-y)][2(x+2y)-3(x-y)]
=(2x+4y+3x-3y)(2x+4y-3x+3y)
=(5x+y)(-x+7y)
=-(5x+y)(x-7y)