已知x-2y＝2,求3x+y-6/4x-y-8的值

已知x-2y=2,求4x-y-8分之3x+y-6 已知2y-x=-3,求[4y(2x-y)-2x(2x-y)]/(2x-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=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：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 化简求值：已知x、y满足：x^2+y^2-4x+6y+13=0 求代数式 的值.(3x+y)^2-3(3x-y)(x+y)-(x-3y)(x+3y)急用！ 已知x-2y＝2,求3x+y-6/4x-y-8的值 已知x-2y＝2,求3x+y-6/4x-y-8的值 要过程 已知(x+2y)(2x-3y)=y(y-4x),试求x/y的值 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 已知x和y满足x＋3y＋|3x－y|＝19,2x＋y＝6,求x,y的值 已知x^3+xy^2+x+x^2y+y^3+y=0,求5x-6y/3x+4y的值. 已知x+y/2x＝4/3,求x/y 已知 2x-3y/y等于2 求x-y/2x 求x-3y/2x+y