Given cost function is
c(x) =
(20 ≤ x ≤ 400)
where x is the number of thousands of square feet
total revenue will be $0.2 million dollars per thousand square feet
Revenue is 0.2 millions per thousand square feet. we know x is the number of thousand of square feet
So R(x) = 0.2x
We know Profit = Revenue - Cost
P(x) = R(x) - C(x)
![P(x) = 0.2x - (2.1 + 0.12x - 0.0001x^2)](https://img.qammunity.org/2019/formulas/mathematics/high-school/dnmr1ybnlfl2wwfw92soo7f1fmqh27iqq3.png)
![P(x) = 0.2x - 2.1 - 0.12x + 0.0001x^2)](https://img.qammunity.org/2019/formulas/mathematics/high-school/zn2g8id64cjbv164r7en9yq6oi757ktv3j.png)
combine like terms
![P(x) =-2.1 + 0.08x + 0.0001x^2](https://img.qammunity.org/2019/formulas/mathematics/high-school/bo8pehi9y0hz5fm2f5dqql5gzzlkhjf0iz.png)
Profit function is
![P(x) =0.0001x^2 + 0.08x - 2.1](https://img.qammunity.org/2019/formulas/mathematics/high-school/wzm52vephl5k75cehe8k88curj73l7m7j9.png)