若x-3y=2,则7-2x+6y=?
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
若x+y=4,则多项式½(x+y)+4﹙x-y)-3(x-y)-3/2(x+y)-x+y是多少?
若x+2y=-7,2x-y=2,则代数式x-3y=?
若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值
若5x+3y=3x+4y=x+2y+6,则x+y=___
若x+3y=3x+2y=7,则x+y=几?
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=
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(
x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20
{(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20