0.8x+0.9y=130
0.8x-0.9y=0.2,0.2分之0.6x-0.3y=2
解二元一次方程0.8x-0.9y=2 6x-3y=2.
{X+2Y/2+3X-Y/3=5{0.2(X+2Y)+0.8(3X-Y)=4
解方程组 x=3y-6 0.8(x+y)=x+y-13.6
x+y=127 0.5x+0.8y=83 求x和y
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)=?
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