(a)
The profit function, P(x), is
Profit = Revenue - Cost
So,
[tex]P(x)=R(x)-C(x)[/tex]
We can find the simplified profit function, shown below:
[tex]\begin{gathered} P(x)=R(x)-C(x) \\ P(x)=520x-(16000+80x+x^2) \\ P(x)=520x-16000-80x-x^2 \\ P(x)=-x^2+440x-16000 \end{gathered}[/tex]
(b)
To find the profit when 30 units are sold, we substitute x = 30 into the profit function.
So,
[tex]\begin{gathered} P(x)=-x^2+440x-16000 \\ P(30)=-(30)^2+440(30)-16000 \\ P(30)=-3700 \end{gathered}[/tex]
So, there is a loss of $3700.
Or, profit of $ -3700
(c)
To find the profit when 45 units are sold, we substitute x = 45 into the profit function.
So,
[tex]\begin{gathered} P(x)=-x^2+440x-16000 \\ P(45)=-(45)^2+440(45)-16000 \\ P(45)=1775 \end{gathered}[/tex]
The profit is $ 1775
(d)
Break Even is the point where Revenue equal Cost.
So,
[tex]R(x)=C(x)[/tex]
Let's find the number of units to break-even,
[tex]\begin{gathered} R(x)=C(x) \\ 520x=16,000+80x+x^2 \\ 16,000+80x+x^2-520x=0 \\ x^2-440x+16,000=0 \\ (x-40)(x-400)=0 \\ x=40,400 \end{gathered}[/tex]
For x = 40 units, it will break even.