$\mathit{A}$ and $\mathit{B}$ are two points on the $\mathit{x}$-axis and $\mathit{y}$ axis respectively.
(a) Write down the coordinates of $\mathit{A}$ and $\mathit{B}$.
(b) $\mathit{P}$ is a point on $\mathit{A}\mathit{B}$ such that $\mathit{A}\mathit{P}:\mathit{P}\mathit{B}=$ $3:1$. Using section formula find the coordinate of point $\mathit{P}$.
(c) Find the equation of a line passing through $\mathit{P}$ and perpendicular to $\mathit{A}\mathit{B}$.