x+y=68 100x+y=100y+x+2178 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+Y=7(100X+Y)-(10Y+X)=(10Y+X)-(10X+Y) x(x+y)(x-y)-y(y+x)(y-x)=(x-y)( )填空 解方程组：x+y=68 100x+y=100y+x=2178 x+y=68 100x+y=100y+x+2178 解方程组 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=? 328-y/y x 100％=-18％ y=x(x If two even number x,y satisfy equation x×x+100=y×y,x 求 X Y公式X+Y=50Y/X=3X+Y=100Y/X=3求 x y...公式 x+x+x+x+y+y+y=56 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) （x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x