若x+y=-3 3x-3y=
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
若x+7y=y-3x,求x
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)
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=
若3x=7y,则y分之x= ,x:(x:y)=
若3x=7y,则y比x= ,x:(x+y)=
若变量x,y满足约束条件{x>=-1;y>=x;3x+2y
若3x-5y=0,则x+y/x=(),x-y/y=(),2x-3y/2x+3y=( )
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(
若x-y/x+y=5,求x-y/2x+2y+5x+5y/3x-3y的值
若x=-1/4,能否确定代数式(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)的值?