[-(x-y)^2/xy]^-4*(y^2-xy/x)^3*(x^4/y^10)÷(xy-y^2/x)^-5=-y(y-x)^2求计算过程已知2x-3y=2,求9^-x * 27^y的值（结果等于1/9)

因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) (x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) 计算:2xy/(x+y)².(x+y)/4y (x^2+2xy+y^2-4xy)*(x^2-2xy+y^2+4xy) (x^-4y^)/(x^+2xy+y^)/(x+2y)/(2x^+2xy) 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 化简：3x^2-[5xy-(x^y-3xy)+4x^2y-8xy] 计算:4xy-(x+y)^2/xy(x+y)(x-y)÷x^2+xy-2y^2/x^2y+2xy^2 化简2(x²y+xy)-3(x²y-xy)-4x²y 2x(x-y)+4xy(y-x) 因式分解2x(x-y)+4xy(y-x) 因式分解 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 因式分解x^2(x-y)-4xy(x-y)-4y^2(y-x) xy-2{xy-[3x^2y-(4xy^2+0.5xy)]+4x^2y}+6xy^2 （X-3xy+4xy-y）-[-2x-2（xy-3/2xy）-y]+6xy的过程 x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 3(x^2y+xy)-4(xy-2x^2y)-(-xy) 5x^3y*(-3y)^2+(-6xy)^2*(-xy)+xy^3*(-4x^2) 当x-y=2xy时,求4x-3xy-4y/xy