Answer
$y\lt-\dfrac{10}{3}$
Work Step by Step
Using the properties of inequality, the solution to the given inequality, $
5-6y\gt25
,$ is
\begin{array}{l}\require{cancel}
-6y\gt25-5
\\\\
-6y\gt20
\\\\
y\lt\dfrac{20}{-6}
\\\\
y\lt\dfrac{\cancel{2}\cdot10}{\cancel{2}\cdot(-3)}
\\\\
y\lt\dfrac{10}{-3}
\\\\
y\lt-\dfrac{10}{3}
.\end{array}