xy/3x+2y=1/8 xy/2x+3y=1/7
xy/3x+2y=1/8 xy/2x+3y=1/7
(x+2y-3xy)-(-2x-y+xy),其中x+y=1/2,xy=-1/2
已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y=
已知3/(x-y)=1/xy 求(-x-2xy+y)/ (2x+3xy-2y)
已知:x-y=1,xy=-2.求:(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
x-y=1,xy=2.求:(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
.已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
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
先化简,再求值 ⒈2(Xy+Xy)-3(Xy-xy)-4Xy,其中X=1,y=-1
已知1/x-1/y=2,求3x+7xy-3y/2x-3xy-2y
已知1/x+1/y=8,求2x-3xy+2y/x+2xy+y的值