(3/x-2/y) / (4x/y - 9y/x) =

(x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x+3y-4)(2x-y) 计算（2x-3y)(x+4y)-(3x+y)(x-2y)（2x-3y)(x+4y)-(3x+y)(x-2y) 因式分解(x-2y)(x-3y)+(x-4y)(x-5y)+（x-3y)(x-5y)+(x-2y)(x-4y) x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² (2x+y)(2x-3y)+x(2y+y) 2a(x-y)-4b(x-y) (2x-y)(2x+y)-2(3x-4y)(4y+3x) (3x-y)(y+3x)-2(4x-3y)(4x+3y) x^4+x^3y+x^2*y^2+y^3x+y^4分解因式 (x-3y)(y+2x)-(4y-3x)(3x+4y)计算 5/4(x+y)(-x-y)^3*[-4/3(x-y)]*[-3/5(y-x)^2] 2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 5x^3y(x-y)^3-10x^4y^3(y-x)^2因式分解 5x^3y(x-y)^3-10x^4y^3(y-x)^2 (x-4y)(2x+3y)-(x+2y)(2y-x) (2x-y)(3x-4y)-2(x-y)(2x-5y)简便运算 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 81/8*(-x-y)^6*(x-y)^3*4/9(x+y)^4*(y-x)^2