(-1/3x^2y)(2xy-3x^2y^2-5)
1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y)
已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y=
计算:(5-xy/x^3-x^2y)/(1-5/xy)^2*(y-x)^3
(x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)
计算3xy[2xy-x(y-2)+x-1]
5x^2y/-1/2xy*3xy^2
(x+y)(x-y)-(2xy+3y)平方
若x+y=-1,则x^4+5x^3y+x^2y+8x^2y^2+xy^2+5xy^3+y^4=( )
[x(x^2y^2-xy)-y(x^2-x^3y)]/3x^2y
【(x-y)^3(x^1/2+y^1/2)^-3+3(x根号y-y根号x)】/(x根号x+y根号y)+(2xy根号xy-
5xy平方-2x平方y+[3xy平方-(4xy-2x平方y-2x平方y)],其中x=-2,y=-1求值
[-(x-y)^2/xy]^-4*(y^2-xy/x)^3*(x^4/y^10)÷(xy-y^2/x)^-5=-y(y-