$$f ( x ) = \frac { y } { 1 - y } g ( 0 ) = \frac { y } { 1 - y } , f ( y ) = 8 ( y ) = 2 ( y ^ { 2 } )$$
$fx=0\text{ and }y=0,\left(f=8\text{ and }y=4\right)\text{ or }y=0$
$\left\{\begin{matrix}x\in \mathrm{R}\text{, }&f=0\text{ and }y=0\\x=0\text{, }&y=0\end{matrix}\right.$
$y=0$
$x=0\text{ or }f=0$
