当x=4,y=10;x=9,y=16;x=16,y=22;x=36,y=?
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
已知4x=9y求(1)x+y/y (2)y-x/2x
x+x+x+y=52 y+y+y+x=36求x
二元函数f(x,y)=x+y/x-y,求f(y/x,x/y)
已知2x-y=10,求[(x²+y²)-(x-y)²+2y(x-y)]/4y
[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013
解方程组 10(x-y)=3(x+y)+15 6(x+y)=4(2x-y)+16
) y=cos(x-y)
指数函数y=3^x当x
x+y=5; x^y+y^x=17
因式分解下列式子:x(x-y)+y(y-x)=?
当x、y满足x>=0,y>=x,2x+y+k