若3x=4,9y=7,则3x-2y=

若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 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2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 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+y)^2=9,x^2+y^2=7,则xy=?已知（x+y)^2=9,x^2+y^2=7,则xy=?已知（x+y)^2=4,（x-y）^2=3,则x^2+y^2=?若x^2+y^2=3,xy=1,则x-y=? 若x+3y=3x+2y=7,则x+y=几? 若X、Y满足方程2X-3Y=-5 4X+9Y=-7,则X+Y的值为? 若x/y=4/3 则3x+2y/2x-5y= 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若3x=7y,则y比x= ,x:（x+y）= 若7x+6(x-y)=-4,3x-4(y-x)=18,则x-y=__ 9y=3x-(x-1),4(x+y)-(2x+4)=8y