Answer
There exists an interval around the value $a=4$, such that
$f(4)\geq f(x)$ for all x in that interval.
Work Step by Step
The function value $f(a)$ is a local maximum value of the function f if
$f(a)\geq f(x)\quad$ for all x near a.
In this case we also say that f has a local maximum at x=a.
For this question,
there exists an interval around the value $a=4$, such that
$f(4)\geq f(x)$ for all x in that interval.
