若x+2y=3,则3x+6y-9=?

若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若2x=3y,则(x*x+y*y)/x*x=? 若2x+3y=2004,则代数式2(3x-2y)-(x-y)+(-x+9y)=... 若5x+3y=3x+4y=x+2y+6,则x+y=___ 若2x+y=2012,则代数式2(3x-2y)-(x-y)+(-x+9y)= 已知x-2y=3,则(2x+y-6)/(3x-y-9)=? 若x^2-y^2=6 x+y=3 则x-y=多少 若2x+2y=6x-3y,则x比y= 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 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2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 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（） 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 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