Step-by-step explanation:
I think you mean : YOU want to know the local minimum and maximum values, so that you can answer the question.
we are not doing it for "them", we are doing it for YOU. you are the only one benefiting from the exercise. nobody else. that is why you are supposed to do it.
so, now, focus.
what does that mean : local maximum and local minimum ?
what do you think ?
is the functional value displayed to the right and left of the graph ?
no. the functional value is the y-value to a given x-value and is displayed up and down on the graph.
so, we are looking for some maximum and minimum values in the up/down direction.
where will be the (local) maximum compared to the (local) minimum value ? above or below the minimum value ?
since going up makes the y-value larger, the maximum will be above the minimum, and the minimum will be below the maximum.
are we looking for the overall maximum and minimum ?
no, we are looking for local (that means just in the near neighborhood of the point) maximum and minimum values.
that means that when going left or right of the local maximum value, the curve will go down, but might later go back up again (and then maybe even higher than the maximum we found before).
and when going left or right of the local minimum value, the curve will go up, but might later go back down again (and then maybe even lower than the minimum we found before).
so, look at the graph : where is the curve going up and then suddenly turns around and goes down again ? at what point is that ?
aha, at x = -6 (and the corresponding local maximum y-value = 0). that is our local maximum.
the local maximum value is therefore 0, at the local maximum point (-6, 0).
and at what point is the curve suddenly turning from going down to going up again ?
aha, at x = -2 (and the corresponding local minimum y-value = -8). that is our local minimum.
the local minimum value is therefore -8, at the local minimum point (-2, -8).
to make the difference between local and general maximum/minimum points clearer, the graph indicates that the general maximum is +infinity, and the general minimum is -infinity.
in other words, there are no general maximum and minimum values, as infinity cannot be reached ever. only after infinity, which is not a possible number for any x- value.