Given data:
The expression for the profit function is y=-100(x-9)(x-17).
Differentiate teh above expressionn and equate to zero, in order to maimize the profit function.
[tex]\begin{gathered} \frac{dy}{dx}=0 \\ -100\frac{d}{dx}(x-9)(x-17)=0 \\ -100(x-9)\frac{d(x-17)_{}}{dx}-100(x-17)\frac{d(x-9)}{dx}=0 \\ -100(x-9)-100(x-7)=0 \\ -100(x-9+x-7)=0 \\ 2x=16 \\ x=8 \end{gathered}[/tex]Thus, 8 T-shirts must be sold in order to maximmize tthe profit.
