Idon't understand how to solve this, can someone explain?

The answer is:

The axis of symmetry of the parabola is a line that cuts the parabola in two symmetric halves.

We can find the axis of symmetry of any parabola using the following formula:

We are given the parabola:

Where,

So, finding the axis of symmetry we have:

So, the axis of symmetry of the parabola is:

Have a nice day!

just get this app called photo math it should be able to do those