Use the chain rule to find the derivative of
f(x)=\displaystyle {f{{\left({x}\right)}}}=5e2x44x7\displaystyle {5}{e}^{{-{2}{x}^{{4}}-{4}{x}^{{7}}}}

Use e^x for ex\displaystyle {e}^{{x}}.
f(x)=\displaystyle {f}'{\left({x}\right)}=