Find the inverse Laplace transform $f(t) = {\mathcal L}^{-1} \left\lbrace F(s) \right\rbrace$ of the function $\displaystyle F(s) = \frac{720}{s^{6}}-\frac{6}{s}$.

$\displaystyle f(t) = {\mathcal L}^{-1} \left\lbrace \frac{720}{s^{6}}-\frac{6}{s} \right\rbrace =$ help (formulas)