Whenever you face the problem that deals with maxima or minima you should keep in mind that minima/maxima of a function is always a point where it's derivative is equal to zero.
To solve your problem we first need to find an equation of net benefits. Net benefits are expressed as a difference between total benefits and total cost. We can denote this function with B(y).
B(y)=b-c
B(y)=100y-18y²
Now that we have a net benefits function we need find it's derivate with respect to y.

Now we must find at which point this function is equal to zero.
0=100-36y
36y=100
y=2.8
Now that we know at which point our function reaches maxima we just plug that number back into our equation for net benefits and we get our answer.
B(2.8)=100(2.8)-18(2.8)²=138.88≈139.
One thing that always helps is to have your function graphed. It will give you a good insight into how your function behaves and allow you to identify minima/maxima points.
Answer:
B. $4.75
Step-by-step explanation:
3(4) + 7 = 19
19/4=4.75
We don't really have to put this in slope intercept form; it would clearly end up as
y = -4x + something
so we know the slope is -4.
Answer: C) -4
Answer:
hi. this is the way
Step-by-step explanation:
this is the process of doing it. hope you like it
Answer:
x = 8/3
Step-by-step explanation:
2x+4 = -x + 3 + 9
3x = 3 + 9 -4
3x = 8
x = 8/3