Using the vertex of the quadratic function, it is found that:
a) The maximum number of customers in the store is at 12 P.M.
b) 75 customers are in the store at this time.
The number of customers in x hours after 7 AM is given by:

Which is a quadratic equation with coefficients 
Item a:
The maximum value, considering that a < 0, happens at:

Hence:

5 hours after 7 A.M, hence, the maximum number of customers in the store is at 12 P.M.
Item b:
The value is y(5), hence:

75 customers are in the store at this time.
A similar problem is given at brainly.com/question/24713268
Y=2x+2 describe the best fit.
first find x and y intercept of a line
x intercept where y=0 is x=-1 and y intercept where x=0 is y=2
11 5/8 + 9 1/2= 21 1/8
3/4 - 2/5= 7/20
4 5/6 - 2 1/2= 2 1/3
I think these are right, I apologize if they are wrong.