$\left\{\begin{matrix}a=\frac{A}{15x}\text{, }&x\neq 0\\a\in \mathrm{C}\text{, }&A=0\text{ and }x=0\end{matrix}\right.$

$\left\{\begin{matrix}a=\frac{A}{15x}\text{, }&x\neq 0\\a\in \mathrm{R}\text{, }&A=0\text{ and }x=0\end{matrix}\right.$

$A=15ax$