若x-y=2,x y=-3,则2(x-y)^2-1/2(x
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于
若全集I={(x,y)|x,y∈R},集合M={(x,y)|(y-3)/(x-2)},N{(x,y)|y=x=1},则(
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
(3x-y)^2+(3x+y)(3x-y),x=1,y=-2
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
若变量x,y满足约束条件{x>=-1;y>=x;3x+2y
若x,y满足|2x-y-3|+|3x+2y+1|=0,则x= y=
1、x(x-y)(x+y)-x(x+y)^2