2x^2-3xy-2y^2+3x+4y-2 化简

化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) （-3x^y+2xy)-( )=4x^+xy (x+y)(x-y)-(2xy+3y)平方 [x(x^2y^2-xy)-y(x^2-x^3y)]/3x^2y 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) 已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)} [-(x-y)^2/xy]^-4*(y^2-xy/x)^3*(x^4/y^10)÷(xy-y^2/x)^-5=-y(y- x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 已知x-y=4xy，则2x+3xy-2yx-2xy-y 化简:-3{y-(3x^2-3xy)}-{y+2(4x^2-4xy)} 化简4xy-3y²-3x²+xy-3xy-2x²+x²-2y²