$$x ^ { 8 } + \frac { 1 } { x ^ { 8 } } = a A \times + \frac { 1 } { x } \quad x ^ { 2 } - \frac { 1 } { x ^ { 2 } } \quad x ^ { 4 } - \frac { 1 } { x ^ { 4 } }$$
$\left\{\begin{matrix}A=\frac{x^{16}+x^{10}+x^{4}+1}{ax^{9}}\text{, }&x\neq 0\text{ and }a\neq 0\\A\in \mathrm{C}\text{, }&-x^{16}-x^{10}-x^{4}-1=0\text{ and }a=0\text{ and }x\neq 0\end{matrix}\right.$
$\left\{\begin{matrix}a=\frac{x^{16}+x^{10}+x^{4}+1}{Ax^{9}}\text{, }&x\neq 0\text{ and }A\neq 0\\a\in \mathrm{C}\text{, }&-x^{16}-x^{10}-x^{4}-1=0\text{ and }A=0\text{ and }x\neq 0\end{matrix}\right.$
$A=\frac{x^{16}+x^{10}+x^{4}+1}{ax^{9}}$
$x\neq 0\text{ and }a\neq 0$
$a=\frac{x^{16}+x^{10}+x^{4}+1}{Ax^{9}}$
$x\neq 0\text{ and }A\neq 0$