y+y+x=10,x+y+x=8,y=?,x=?

【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 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 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai ) y=cos(x-y) 已知/x/+x+y=10,/y/+x-y=12.求x+y的值 x+y=5; x^y+y^x=17 因式分解下列式子：x(x-y)+y(y-x)=? 根据x+x+x+y+y=54,x+x+y+y+y=56,求出x.y的值 已知2x-y=10,求[(x²+y²)-(x-y)²+2y(x-y)]/4y 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)