Answer
$-\dfrac{3}{4}$
Work Step by Step
Cancelling the common factor between the numerator and the denominator, the given expression, $
\dfrac{27}{-36}
,$ simplifies to
\begin{array}{l}\require{cancel}
\dfrac{\cancel{9}\cdot3}{\cancel{9}\cdot(-4)}
\\\\=
\dfrac{3}{-4}
\\\\=
-\dfrac{3}{4}
\end{array}