2Y：30%=3X：50%求X:Y

2Y：30%=3X：50%求X:Y 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 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 已知|x|=2,|y|=3,|x+y|=-(x+y)求x-y (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) y=3(x-y),x=2(x-y)求x,y的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 |x|+|y|=30 2|x|-3|y|=20 求x,y x+y/2+ x-y/2=6 2(x+y)-3x+3y=24 求X Y 已知2y-x=-3,求[4y(2x-y)-2x(2x-y)]/(2x-y {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 已知:3x-5y=0,求x/y,x-y/y,x-y/x 已知：x(x-50y)+xy=50y^2,求：(x-y):y=? 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 求几个方程组的答案 ｛2x+y=2 {3x-y=7 x=?y=?{x+2y=50 {3x=2y+6 x=?y=?{x+y=40 {10x+8y=370 x、y=?{x+y=5.8 {y=3x+0.6 x=?y=?