若x₁=y-1,x₂=2y+3,则y=
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)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(
设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于
若x,y满足|2x-y-3|+|3x+2y+1|=0,则x= y=
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3x-5y=0,则x+y/x=(),x-y/y=(),2x-3y/2x+3y=( )
若x=-1/4,能否确定代数式(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)的值?
(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
若变量x,y满足约束条件{x>=-1;y>=x;3x+2y
若x+y=-1,则x^4+5x^3y+x^2y+8x^2y^2+xy^2+5xy^3+y^4=( )
若实数x,y满足2x*X+3y*y=1,S=3x*x-2y*y,则S的取值范围为