{x+y=100 0.7x+0.8y=74
解两个二元一次方程组{x+y=100,0.7x+0.8y=74,消元法,加减法都行,{12x+15y=180,11x+1
X+Y=7(100X+Y)-(10Y+X)=(10Y+X)-(10X+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)=?
0.8X+0.6Y=100 0.7(X+Y)=98方程解
If two even number x,y satisfy equation x×x+100=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
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)