｛4（x+y)=80.5(x-y)=80.方程式

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 化简 x / y(x+y) - y / x(x+y) = 7x:4y,x:y=( ):( (x-4y)(2x+y)= 5x-4y(y-x)=? x(x+y)(x-y)-y(y+x)(y-x)=(x-y)( )填空 x+x+x+y=60 .x-y=4 ｛4（x+y)=80.5(x-y)=80.方程式 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? 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 3X+X=( ) Y+4Y-3Y=( ) x+y／y=5／4,则x／y=---------------- x*x+2x+y*y-4y+5=0 x= y= 如果|X|=4 |Y|=2 且|X+Y|=X+Y 求X+Y {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1