Answer
$-\dfrac{1}{5}$
Work Step by Step
Cancelling the common factor between the numerator and the denominator, the given expression, $
\dfrac{-3}{15}
,$ simplifies to
\begin{array}{l}\require{cancel}
\dfrac{\cancel{-3}}{\cancel{-3}\cdot(-5)}
\\\\=
\dfrac{1}{-5}
\\\\=
-\dfrac{1}{5}
\end{array}
