X平方（3X+5Y）平方-Y平方（5X+3Y)平方
问题描述：
X平方（3X+5Y）平方-Y平方（5X+3Y)平方
答
X平方（3X+5Y）平方-Y平方（5X+3Y)平方
=(3X²+5XY)²-(5XY+3Y²)²
=(3X²+5XY+5XY+3Y²)(3X²+5XY-5XY-3Y²)
=(3X²+10XY+3Y²)(3X²-3Y²)
=(3X+Y)(X+3Y)*3(X+Y)(X-Y)
=3(3X+Y)(X+3Y)(X+Y)(X-Y)
答
原式=x^2(3x+5y)^2-y^2(5x+3y)^2
=[x(3x+5y)+y(5x+3y)][x(3x+5y)-y(5x+3y)]
=(3x^2+5xy+5xy+3y^2)(3x^2+5xy-5xy-3y^2)
=(3x^2+10xy+3y^2)(3x^2-3y^2)
=3(x+y)(x-y)(3x+y)(x+3y)
即为所求