we have

Complete the square. Remember to balance the equation by adding the same constants to each side


Rewrite as perfect squares


therefore
the answer is

The sketch of the parabola is attached below
We have the focus

The point

The directrix, c at

The steps to find the equation of the parabola are as follows
Step 1
Find the distance between the focus and the point P using Pythagoras. We have two coordinates;

and

.
We need the vertical and horizontal distances to find the hypotenuse (the diagram is shown in the second diagram).
The distance between the focus and point P is given by

Step 2
Find the distance between the point P to the directrix

. It is a vertical distance between y and c, expressed as

Step 3
The equation of parabola is then given as

=


⇒ substituting a, b and c


⇒Rearranging and making

the subject gives
We have been given two functions
and
. We are asked to find
.
We will use composite function property
to solve our given problem.
Now we will combine like terms as:


Therefore, the value of
would be
.