Answer:
The possible values are a = -2.5 or a = 4.5.
Step-by-step explanation:
Composite function:
The composite function of f(x) and g(x) is given by:

In this case:


So

Value of a so that the y-intercept of the graph of the composite function (fog)(x) is (0, 25).
This means that when
. So


Solving a quadratic equation, by Bhaskara:



The possible values are a = -2.5 or a = 4.5.
The answer is option c.
That is, the wrong step in step 6. It was written that the center of the circunference is the point (2.1). However, the general equation of a circumference is:
(X- (a)) ^ 2 + (Y- (b)) ^ 2 = r ^ 2
Where the point (a, b) is the center of the circle.
So for this case the point for the center is: (-2, -1)