x+y=40 1.2x+1.6y=60

x+y=40 1.2x+1.6y=60 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 X+Y=40,(X*Y)/(X+Y)=7.5 化简 x / y(x+y) - y / x(x+y) = x(x+y)(x-y)-y(y+x)(y-x)=(x-y)( )填空 x+x+x+y=60 .x-y=4 x+y=450;40%x+30=60%y {x+y=450,60%y-40%x=30 1000+y=60x 1000-y=40x x+x+x+x+y=40 x+y= 13x=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=? y=x(x x+y/3+x-y/2=6 4(x+y)-2(x-y)=40 已知 x:y=1.6:1.2,求(x-y):(x+y)的值 x+y=160,40%x+75%y=60%*160 x=? y=? x+y=160,40%x+75%y=60%*160 x=?y=? x+x+y+y+y+y=80 x+x+y+y=40 问XY=?