|x|=99 |y|=98 x＞y x,

|x|=99 |y|=98 x＞y x, 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 y=x(x x+x+x+x+y+y+y=56 x^2+y^2=15,x+y=7,x＞y,求x-y 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=? 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 推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做. 已知|x|=99,|y|=98,并且x大于y.求x,y的值；若x小于y,那么x,y的值又如何呢? x+y=5; x^y+y^x=17 X+Y=40,(X*Y)/(X+Y)=7.5