This equation has infinite solutions, any real number makes it true.
Given data:
The given table.
The expression for the average temperature is,

Thus, the value of x is 86 degree Fahrenheit.
Answer:
39.34 juniors and 30.1 seniors
I don’t know all of it but....
Axis of symmetry is x=5
Vertex changed to (5,8)
Parabola opens down