[2000+20(x-y)]/x+y = (2000-20y)/y 怎么化简

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 化简 x / y(x+y) - y / x(x+y) = [2000+20(x-y)]/x+y = (2000-20y)/y 怎么化简 x(x+y)(x-y)-y(y+x)(y-x)=(x-y)( )填空 x+x+x+y=20 x+x+y=14 x=?y=? x+y=20,x-y=10,y= x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 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 y=x+2000 3x-y=1000x x+x+x+x+y+y+y=56 已知x+y+y=20,x+y=15求x.y {(x,y) |x|+|y| x>y?x:y x+x+x+y+y=6.4 y+y+y+x+x=7.1 怎么算?