Answer
The theorem can not be applied because
f is not continuous on the closed interval $[-2,1]$.
Work Step by Step
The Mean Value Theorem
If $f$ is continuous on the closed interval $[a, b]$ and differentiable on the open interval $(a, b)$ ,
then there exists a number $c$ in $(a, b)$ such that
$f^{\prime}(c)=\displaystyle \frac{f(b)-f(a)}{b-a}.$
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f is not defined for $x=0\in[-2,1] ,$
so it is not continuous on the closed interval $[-2,1]$.
A premise of the theorem is not satisfied, so the theorem can not be applied.
