若9x^2+y^2+24x-6y+25=0,则xy=

若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x+y/2+ x-y/2=6 2(x+y)-3x+3y=24 求X Y 已知X*X+Y*Y+6X-8Y+25=0 求（Y/X)+(X/Y)-2=? 若x^2+y^2-6x+8y+25=0 则y/x-x/y的值是 若x-y=6,x^2-y^2=24,则x+y=? 若方程组x+2y=6,2x+y=9 那么x+y=? 若9x^2+y^2+24x-6y+25=0,则xy= 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) (x+y)^2+6(x+y)+9 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 若2x^2-6xy+9y^2-4x+4=0,则y/x-x/y=若2x^2-6xy+9y^2-4x+4=0,则y/x-x/y=? 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.x+y.y+8x+6y+25=0,求代数式(x.x-4y.y)/(x.x+4xy+4y.y)-x/(x+2y)的值 (x-2y)^2-6(2y-x)(x+y)+9(x+y)^2因式分解 x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 若f(x+y,y/x)=x^2-y^2,则F(X,Y)= [(2x-y)(2x+y)+y(y-6x)]÷2x=?