Since the cost function is
![C(x)=-19x^2+61000x+18324](https://img.qammunity.org/2023/formulas/mathematics/college/5xrfc8gtdf423qmkm2e38wb5dt1ildof1c.png)
Since the revenue function is
![R(x)=-23x^2+149000x](https://img.qammunity.org/2023/formulas/mathematics/college/g760nno0dxkf7x0pujz30zdkefpmdkdkha.png)
Since the profit function is
![P(x)=R(x)-C(x)](https://img.qammunity.org/2023/formulas/mathematics/high-school/3r9w44q173wp0f0kgyb63izfoqnf6o9s8j.png)
Then we will subtract C from R
![\begin{gathered} P(x)=-23x^2+149000x-(-19x^2+61000x+18324) \\ P(x)=-23x^2+149000x+19x^2-61000x-18324 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/rv5wvtsxppoeyr2n82jbc23xjvv81bpa1h.png)
Add the like terms
![\begin{gathered} P(x)=(-23x^2+19x^2)+(149000x-61000x)-18324 \\ P(X)=-4x^2+88000x-18324 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/2bt8ajaw03jx29wc9rsvnchb2l4ux3pm44.png)
Now, we will differentiate P(x) and equate the answer by 0 to find x maximum
![\begin{gathered} P^(\prime)(x)=-4(2)x^(2-1)+88000(1)x^(1-1) \\ P^(\prime)(x)=-8x+88000 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/q8abh6vrcwn5ye52j54l13tpmwr4920bpi.png)
Equate P' by 0 to find x
![\begin{gathered} P^(\prime)(x)=0 \\ -8x+88000=0 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/pwkobc7m1uieo94ckkul54s3cytxwg91kx.png)
Subtract 88000 to both sides
![\begin{gathered} -8x+88000-8000=0-88000 \\ -8x=-88000 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/7q7j1qsih1looc083en5tmcroxk0lvr5gj.png)
Divide both sides by -8
![\begin{gathered} (-8x)/(-8)=(-88000)/(-8) \\ x=11000 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/swxm4trbs243hk9vw37iyas66vpebbs89s.png)
The company should produce 11000 Phones to maximize the profit