$f\left( x \right)+2f\left( -x \right)={{x}^{7}}-{{x}^{3}}+x-5\begin{matrix}    {} & (1)  \\ \end{matrix}$  $\xrightarrow{x\to -x}f\left( -x \right)+2f\left( x \right)=-{{x}^{7}}+{{x}^{3}}-x-5\begin{matrix}    {} & (2)  \\ \end{matrix}$   $\to -3f\left( x \right)=3{{x}^{7}}-3{{x}^{3}}+3x+5$ $\to -3f\left( x \right)=3{{x}^{7}}-3{{x}^{3}}+3x+5\Rightarrow f\left( x \right)=-{{x}^ {7}}+{{x}^{3}}-x-\frac{5}{3}$  ${{x}^{2}}-2=0\Rightarrow {{x}^{2}}=2$  $f\left( x \right)=-{{\left( {{x}^{2}} \right)}^{3}}x+({{x}^{2}})x-x-\frac{5}{3}\xrightarrow{{{x}^{2}}=2}R\left( x \right)=-8x+2x-x-\frac{5}{3}$  $\Rightarrow R\left( x \right)=-7x-\frac{5}{3}=ax+b\Rightarrow \left( a,b \right)=\left( -7,\frac{5}{3} \right)$