(-3x^2y)x(-1/3xy^2)^3
计算3xy[2xy-x(y-2)+x-1]
1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y)
(x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)
xy(xy+1)+(xy+3)-2(x+y+2分之一)-(x+y-1)的平方
(-3分之1xy)的平方×[xy(2x-y)-2x(xy-y的平方)]
1/2xy-{1/2xy-[1/3x^2y-(x^2y-xy)]+1/3x^2y}
计算:(5-xy/x^3-x^2y)/(1-5/xy)^2*(y-x)^3
已知3/(x-y)=1/xy 求(-x-2xy+y)/ (2x+3xy-2y)
已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y=
(x+2y-3xy)-(-2x-y+xy),其中x+y=1/2,xy=-1/2
已知:xy+x=-1,xy-y=-2,求多项式-x-[2y-2(xy+x)的平方+3x]+2[x+(xy-y)的平方]的
已知:x-y=1,xy=-2.求:(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值