若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于

若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若2x=3y,则(x*x+y*y)/x*x=? 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) 若x+2y分之x-y=3,则代数式x+2y分之2（x-y)-3(x-y)分之x+2y的值为 若x+y=4,则多项式1/2(x+y)+4(x-y)-3（x-y）-3/2(x+y)-x+y值是（） 若x-y不等于0,2x-3y=0,则分式(10x-11y)/(x-y)的值是（）?(10x-11y)/(x-y) =[(8x-8y)+(2x-3y)]/(x-y) =8为什么8X-8Y=8？(10x-11y)/(x-y)=[(8x-8y)+(2x-3y)]/(x-y)=8+(2x-3y)]/(x-y)=8+0=8 若f(x+y,y/x)=x^2-y^2,则F(X,Y)= 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若x:y=3则x:(x+y)= x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 若x、y互为相反数,则x+2x+3x+...100x+100y+99y+98y+...+y 若x,y满足|2x-y-3|+|3x+2y+1|=0,则x= y= 若2x+3y=2004,则代数式2(3x-2y)-(x-y)+(-x+9y)=... 若线段x ,y 满足[2x-3y]*[3x+2y]=0 则x/y=? 若5x+3y=3x+4y=x+2y+6,则x+y=___ 若x-y=2,x+y=-3,则2(x-y)²-½(x+y)²=? 若2x+y=2012,则代数式2(3x-2y)-(x-y)+(-x+9y)=