若1x+1y
若x-y=1,求代数式x(x-y)+y(y-x)+2013的值
设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于
1、x(x-y)(x+y)-x(x+y)^2
(1)(x^2/x)-y-x-y
若|x+2y-1|+y²+4y+4=0,求(2x-y)²-2(2x-y)(x+2y)+(x+2y)&
若变量x,y满足约束条件{x>=-1;y>=x;3x+2y
若实数x,y满足x-y+1>=0,x+y>=0,x
若实数x,y满足x-y+1》=0,x+y>=0,x
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=-1/4,能否确定代数式(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)的值?
若|x+y-1|+(x-y-2)²=0,求代数式(x+2y)(x-2y)-(2x-y)(-y-2x)的值.
[(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y