The cost function has a fixed part ($40,000) and a variable part, that depends on the number of CD's (14x), so we can write the cost function as:
[tex]C(x)=40000+14x[/tex]The revenue is equal to the unit price times the number of CD's:
[tex]R(x)=93x[/tex]The profit function is the difference between the revenue and the cost:
[tex]\begin{gathered} P(x)=R(x)-C(x) \\ P(x)=93x-40000-14x \\ P(x)=(93-14)x-40000 \\ P(x)=79x-40000 \end{gathered}[/tex]The number of CD's that must be produced and sold to breakeven happens when C(x)=R(x) or P(x)=0, so we can write:
[tex]\begin{gathered} P(x)=0 \\ 79x-40000=0 \\ 79x=40000 \\ x=\frac{40000}{79} \\ x\approx506.32\approx507 \end{gathered}[/tex]Answer:
C = $40000 - $14x
R = $93x
P = $79x - $40000
The breakeven number of CD's is 507 units.