x,y∈R+求证:(x+y)(x^2+y^2)(x^3+y^3)>=8x^3y^3
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(
已知x,y∈R*,x+y=1,求证2/x+1/y≥3+2根号2
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=
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)
已知集合A={(x,y)| (y-3)/ (x-1)=2,x,y∈R},B={(x,y)| 4x+ay=16,x,y∈
[(3x+y)(x-y)-(2x+3y)(x-y)]*(x-y)
化简:(x-3y)(x+y)-(x-2y)(x+2y)-(x-y)平方
【x-3y][x+y]-[x-2y][x +2y]-[x-y
有这样一道题:"计算(2*x*x*x-3*x*x*y-2*x*y*y)-(x*x*x-2*x*y*y+y*y*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
计算(x+y)(x+y)^2(-x-y)^3