What is the quotient of -15x^6 divided by -5x^3?

$\frac{- 15 {x}^{6}}{- 5 {x}^{3}}$
We can then use this rule for exponents to divide the $x$ terms:
${x}^{\textcolor{red}{a}} / {x}^{\textcolor{b l u e}{b}} = {x}^{\textcolor{red}{a} - \textcolor{b l u e}{b}}$
$\frac{- 15 {x}^{\textcolor{red}{6}}}{- 5 {x}^{\textcolor{b l u e}{3}}} \to 3 {x}^{\textcolor{red}{6} - \textcolor{b l u e}{3}} \to 3 {x}^{3}$