1. **State the problem:** We need to write a system of linear equations to model the ticket sales for a high school football game. 2. **Define variables:** Let $x$ be the number of student tickets sold. Let $y$ be the number of adult tickets sold. 3. **Write equations based on the problem:** - The total number of tickets sold is 729: $$x + y = 729$$ - The total money collected is 2995, with student tickets costing 3 and adult tickets costing 5: $$3x + 5y = 2995$$ 4. **System of equations:** $$\begin{cases} x + y = 729 \\ 3x + 5y = 2995 \end{cases}$$ This system models the situation algebraically, where $x$ and $y$ represent the number of student and adult tickets sold respectively. **Final answer:** $$\boxed{\begin{cases} x + y = 729 \\ 3x + 5y = 2995 \end{cases}}$$