The expression
$\displaystyle \frac{{{\left({4}{y}^{{5}}\right)}^{{5}}}}{{{4}{y}^{{6}}}}$
equals $\displaystyle {c}{y}^{{{e}}}$ where
the coefficient $\displaystyle {c}$ is , the exponent $\displaystyle {e}$ of $\displaystyle {y}$ is .