若2X-Y=3,则4X-2X-Y=?

若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若2x=3y,则(x*x+y*y)/x*x=? 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（） (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若5x+3y=3x+4y=x+2y+6,则x+y=___ x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 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x,y,z成等差数列,则(z-x)^2-4(x-y)(y-x)= 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) 2x-y/x+y=4,则4x-2y/2x+2y+3x+3y/2x-y 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=-1/4,能否确定代数式(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)的值? 若X=负四分之一,能否确定代数式(2X-Y)(2X+Y)+(2X-Y)(Y-4X)+2Y(Y-3X)的值? 若f(x+y,y/x)=x^2-y^2,则F(X,Y)= 2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2