3(x+y)+2(x-y)=20 0.3x+0.6y=60 x=?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 3(x+y)+2(x-y)=20 0.3x+0.6y=60 x=?y=? 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)= (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (x+y)(2x-3y)=? 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 已知3x =2y 求x/x+y+y/x-y-y²/x²-y² 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 2x+3y=9 x+y=20 x+y=20 3x-2y=5x+y=203x-2y=5 2元一次方程组 2/x+y+3/x-y=6 4(x+y)-3(x-y)=-20 解方程组;x+y/2=x-y/3=6 4(x+y)-3(x-y)=-20 1/(x+y)-1/(x-y)=-3/20,2/(x+y)+3/(y-x)=-(1/5)急啊!