x·(9x^3y-3xy^2)÷(-3x^2y) [(x+y)^2-(x-y)^2]÷(-4xy) 怎么写

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) (x^2-xy)y÷y-x/xy怎么做? [-(x-y)^2/xy]^-4*(y^2-xy/x)^3*(x^4/y^10)÷(xy-y^2/x)^-5=-y(y- (2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)+2x^4y^2÷(xy)^2 急![(3x+y)²-3(3x-y)(x+y)-(x-3y)(x+3y)]÷(2xy) 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y [x(x^2y^2-xy)-y(x^2-x^3y)]/3x^2y (x+y)(x-y)-(2xy+3y)平方 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) （-3x^y+2xy)-( )=4x^+xy [x(x^2 y^2-xy)-y(x^2-x^3y)]÷3x^2y