Answer: 8
Step-by-step explanation:
I took the test and I got it right.
According to the vertex and the directrix of the given parabola, the equation is:

<h3>What is the equation of a parabola given it’s vertex?</h3>
The equation of a quadratic function, of vertex (h,k), is given by:

In which a is the leading coefficient.
The directrix is at y = k + 4a.
In this problem, the vertex is (1,4), hence:

The directrix is at y = 7, hence:


Hence, the equation is:


More can be learned about the equation of a parabola at brainly.com/question/26144898
Answer:
Josie: 100 + 5x
Allanah: 10 + 20x
x is to represent the unknown variable of how many times they will repeat this process.