\(\displaystyle={f{{\left({x}\right)}}}={5}{x}^{{{4}}}+\frac{{5}}{{2}}{x}^{{3}}-{9}{x}^{{4}}+\sqrt{{2}}{x}^{{2}}+{4}{x}-{1}-{x}^{{0}}-{4}\)

\(\displaystyle={\left({5}{x}^{{4}}-{9}{x}^{{4}}\right)}+\frac{{5}}{{2}}{x}^{{3}}+\sqrt{{2}}{x}^{{2}}+{4}{x}-{6}\)

\(\displaystyle=-{4}{x}^{{4}}+\frac{{5}}{{2}}{x}^{{3}}+\sqrt{{2}}{x}^{{2}}+{4}{x}-{6}\)