Answer:
y=35x+50
35*8=280
280+50=330
yes there will be 10 dollars left
I hope this is good enough:
Check the picture below.
as you can see, the graph of the volume function comes from below goes up up up, reaches a U-turn then goes down down, U-turns again then back up to infinity.
the maximum is reached at the close up you see in the picture on the right-side.
Why we don't use a higher value from the graph since it's going to infinity?
well, "x" is constrained by the lengths of the box, specifically by the length of the smaller side, namely 5 - 2x, so whatever "x" is, it can't never zero out the smaller side, and that'd happen when x = 2.5, how so? well 5 - 2(2.5) = 0, so "x" whatever value is may be, must be less than 2.5, but more than 0, and within those constraints the maximum you see in the picture is obtained.
Step-by-step explanation:
We need to find the value of the function at the indicated value.

Indicated values are : f(-7), f(0), f(6), f(7)
To find f(-7), put x = -7 in the given function

To find f(0), put x = 0 in the given function

To find f(6), put x = 6 in the given function

To find f(7), put x = 7 in the given function

Hence, this is the required solution.
5x7=35
5x7=5x(5+2)
5x7=(5x3)+(5x4)
5x7=20+15
5x7=35
This is how I would do it :)