3x=2y+1;x=9y;求x,y的值?

若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 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 3x=2y+1;x=9y;求x,y的值? 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 y=3(x-y),x=2(x-y)求x,y的值 已知2x-y/x+2y=3,求2(2x-y)/x+2y-9(x+2y)/2x-y+3的值. (x+y)+(2x+0.5y)+(3x+1/6y)+...+(9x+1/72y),当x=2,y=9时,求代数式的值 若x-y=2(x+y),求代数式x-y/x+y+x+y/x-y求代数式 x+y分之x-y+x-y分之x+y 已知:y=ax的3次方+bx+3,当x=-1/2时,y=-7,试求x=1/2时,y的值 已知2x-y=0,求分式【1+（3*y*y*y/x*x*x-y*y*y）】/【1+（2y/x-y）】的值注：x*x*x-y*y*y=（x-y）*（x*x+xy+y*y） 若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值 已知：x+9y=y-3x,求(x^2-y^2)/(x^2+y^2)的值RT 若／X+Y-9／+（2X-Y+3)=0求X与Y的值 若x-y=3,x^2-y^2=1,求x+y的值 已知|2x-3y|+|3x-y-1|=0,求x,y的值. 已知3x-4y/2x+y=1/2 求x/y的值 已知x-2y/y+3x=1/2,求x/y的值