1. **State the problem:** We want to find the baseball ticket prices in 2009 using the previous equation or model given for ticket prices over the years. 2. **Recall the formula:** Suppose the previous equation for ticket prices $P$ as a function of year $t$ is given by $$P = mt + b$$ where $m$ is the rate of change per year and $b$ is the base price at year zero or a reference year. 3. **Identify the year value:** To find the price in 2009, substitute $t = 2009$ into the equation. 4. **Calculate the price:** $$P_{2009} = m \times 2009 + b$$ 5. **Interpretation:** Since 2009 is outside the range of years used to create the model (assuming the data was from years before 2009), this is an **extrapolation** because we are predicting beyond the known data range. **Final answer:** The ticket price in 2009 is $$P_{2009} = m \times 2009 + b$$ and this is an extrapolation.