x+x+x+y+y=21,x+x+x+x+x+y+y=27,求x=?y=?
二元函数f(x,y)=x+y/x-y,求f(y/x,x/y)
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)
x+x+x+y=52 y+y+y+x=36求x
(x*x+y*y)(x*x+y*y)-(x*x+y*y)=12 求x*x+y*y等于多少
[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013
{(x,y) |x|+|y|
x>y?x:y
x+x+x=15,x+y+y=19,求y-x等于几
用递归法求y=x-(x*x*x/3!)+(x*x*x*x*x/5!)-(x*x*x*x*x*x*x/7!)+.
若x+7y=y-3x,求x
y=ln(x^2+e^x) 求Y'X