{x+y=11,600x+800y=7400解方程组

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 化简 x / y(x+y) - y / x(x+y) = x(x+y)(x-y)-y(y+x)(y-x)=(x-y)( )填空 {2x+y=74x+5y=11 [(y*y*y-y)/(xy+1)*(xy+1)-(x+y)*(x+y)]/[(x+y)*y/(x+1)]其中x=-11,y=1/12,化简再求值. x+x+y+y+y=21 ,x+x+y+y+y+y+y=27 ,x ,y=? x+x+y+y+y=21 ,x+x+y+y+y+y+y=27 ,x ,y=? y=x(x 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 6(x+y)的平方-11(x+y)(x-y)+3(x-y)的平方=? x+x+x+x+y+y+y=56 若x,y是正整数,且满足x(x+y)-y(x+y)=11求x+y的值 若x、y为正整数,且满足x(x+y)-y(x+y)=11,求x,y的值 x+x+x+y+y=6.4 y+y+y+x+x=7.1 怎么算? 二元函数f(x,y)=x+y/x-y,求f(y/x,x/y) x-y/x+y=(x-y)²/x²-y²（x≠y)