helpp im super bad at math

Question

(the picture shown is a graph that increases by 40 on the y axis and 2 on the x axis. the parabola is an upward opening one that has a maximum of (5,160) and x intercepts of (0,0) and (10,0) the graph represents a company's profit f(x), in dollars, depending on the price of pencils x, in dollars, sold by the company)

Part A: What do the x-intercepts and maximum value of the graph represent? What are the intervals where the function is increasing and decreasing, and what do they represent about the sale and profit?
(i answered part of it):
the x intercepts shows that the company made no profit when the price of pencils were (0,0) and (0,10). the maximum shows that the company made the most profit at (5,160). (is it right?? if its not plss correct it)

Part B: What is an approximate average rate of change of the graph from x = 2 to x = 5, and what does this rate represent?

Part C: Describe the constraints of the domain.

Answer 1

a parabola that opens up has no maximum.
If the vertex is at (5,160) then the equation is
y = a(x-5)^2 + 160
Since (0,0) is on the graph, that means
a(0-5)^2 + 160 = 0
a = -160/25 = -32/5
So the parabola opens down, not up
y = -32/5 (x-5)^2 + 160

now see what you can do with A and B

Answer 2

ty the main thing i rlly need help on is the interval and the change of rate part
(i messed up on the description i meant downward opening (it wont let me paste the pic))

Answer 3

the avg rate of change is the slope of the line joining the two points on the curve
(2,f(2)) and (5,f(5))
it will be in units of $/pencil