To find the zero of a function , we simply need to solve with regards to . That is, find such that .

To find the min/max of a parabola, we solve with regards to x. Then, for those values of x we find . Say . If then is a minimum point. If , then is a maximum point.

Example:

Let . Find the zeroes of and find its min/max points.

First we'll find the zeroes. Solve :

So .

Now we'll find the min/max points. First we find :

Solve :

So is a critical point. Find :

So is a minimum point, since