Answer:

What is given to you is interval notation. We have the interval start at 0 and end at 8. The value 0 is not included in the interval as indicated by the parenthesis. So we go with a "less than" sign (instead of a "less than or equal to" sign)
The value 8 is included since a square bracket is used here. The use of "or equal to" is needed to make sure the endpoint 8 is included.
So x can be any number between 0 and 8. It can't be 0 but it can be 8.
x = -2, x = 5
=> f(x) = a(x+2)(x-5), a ∈ R
542(1+1/4)
542(4/4+1/4)
542(5/4)
677.5
0.05 is the answer for your question.