9x^2(x-2y)^2-16y^2(2y-x)^2因式分解以下各题都要过程因式分解 y^（n-1）-6y^（n-2）+9y^（n-3） （n＞3而且n为整数）计算：25（x+y）^2-9（x-y）^2 【答案是4（4x+y）（x+4y） 但是为什么?】因式分解：二分

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 化简y(x+y)+(x+y)(x-y)-x^2 (x+y)(x-y)-(x-y)^2如题 (x+y)(x-y)-(x-y)^2 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) 因式分解x(x+y)(x-y)-x(x+y)^2 (x+y)^2-16(x-y)^2 (x+y)^2-16(x-y)^2 16-8（x-y)+(x-y)2 [(x-y)^2-(x+2y)(x-2y)]/y 9(x-y)-12(y-x)^2 (x+y)^2+6(x+y)+9 (x+y)^2-9(x+y)+18 计算:y-x分之x+y+x-y分之y-y-x分之2x-y x^2(x-y)+(y-x) x(x-y)2-(y-x)3 【(x-y)^2+(x+y)(x-y)】除以 2x [(x-y)²+(x+y)(x-y)]除以2x 化简：[(x+y)(x-y)(x+y)^2-2y(x-2y)](-2y) 谢谢!