Answer
$f$ is not differentiable when $x = -4$ and $x = 0$
Work Step by Step
$f$ is not differentiable when $x = -4$ since it has a corner and when $x = 0$ since $f$ is not continuous
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.