Given the price model:
![p=\sqrt[]{81-x^2}](https://img.qammunity.org/2023/formulas/mathematics/college/llk18a6yus09p21j5b3z8qrsp583ez4byu.png)
Where x represents the number of thousands of canisters and p is the price.
(a) If p = 8:
![8=\sqrt[]{81-x^2}](https://img.qammunity.org/2023/formulas/mathematics/college/7i5hn38qshsw746wr3x2d8eakic3npc4p1.png)
Taking the square on both sides:
![\begin{gathered} 8^2=81-x^2 \\ 64=81-x^2 \\ \Rightarrow x^2=17 \\ \Rightarrow x=\sqrt[]{17} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/7vredwy3w580e9dkszamrp0yjb018vnqkd.png)
(b)
If the price is 8, the number of canisters demanded is 1000*x, since x represents the number of thousands of canisters. Then, to the nearest whole number:
![\begin{gathered} \text{Number of canisters demanded }=1000\cdot\sqrt[]{17} \\ \Rightarrow\text{Number of canisters demanded }=4123 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/2fhbzo372c6q8a3c82h6zfwprq24kp74w5.png)