已知x-3y=2,已知x-3y=2,x²-9y²=12已知x-3y=2,x²-9y²=12,求2x+y的值

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知|x|=2,|y|=3,|x+y|=-(x+y)求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2y-x=-3,求[4y(2x-y)-2x(2x-y)]/(2x-y 已知|x+y-3|+(x-y)2=0则 已知2x=3y,则y分之x=< >,y分之x+y=< >. 已知函数y=-x^3-3x(x^2 已知:3x-5y=0,求x/y,x-y/y,x-y/x 已知x=3分之一,y=-2分之一,求代数式x-(x+y)+(x+2Y)-(x+3y)+(x+4y)...-(x+2009y) 已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)X(x-y) 比例线段：已知x/y=2/3,则 x/x+y= ,x-y/x+y= 要过程! 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 已知(x+2y)(2x-3y)=y(y-4x),试求x/y的值 已知x-2y=3,则(2x+y-6)/(3x-y-9)=? 已知2x-3y=0则3x-y比x+2y=