x+y=500 84%x+60%y=500*72%
X-Y=500 (X-300)/Y*100%=120%
二元函数f(x,y)=x+y/x-y,求f(y/x,x/y)
[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013
) y=cos(x-y)
x+y=5; x^y+y^x=17
因式分解下列式子:x(x-y)+y(y-x)=?
X+Y=158X+4Y=72X+Y=15Y=15-X代入8X+4Y=728X+4(15-X)=728X+60-4X=72
方程组x-y=500① x+15%-(y-10%y)=950②
根据x+x+x+y+y=54,x+x+y+y+y=56,求出x.y的值
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)
求y'=y/(y-x)