The general solution of the differential equation $\left(3 x^2-2 x y\right) d y+\left(y^2-2 x y\right) d x=0$ is

If $m$ and $n$ are respectively the order and degree of the differential equation of the family of parabolas with origin as its focus and $X$-axis as its axis, then $m n-m+n=$

The general solution of $\frac{d y}{d x}+y f^{\prime}(x)-f(x) f^{\prime}(x)=0$, $y \neq f(x)$ is