1. **State the problem:** We have the distance function $$D = -60t + 240$$ where $$D$$ is the distance from City A in miles and $$t$$ is the time in hours after Stella leaves her house. We need to find the x-intercept of this equation and interpret it. 2. **Recall the x-intercept definition:** The x-intercept occurs where the graph crosses the $$t$$-axis, meaning the distance $$D$$ is zero. So, set $$D = 0$$ and solve for $$t$$. 3. **Set up the equation:** $$0 = -60t + 240$$ 4. **Solve for $$t$$:** $$-60t + 240 = 0$$ $$-60t = -240$$ $$t = \frac{-240}{-60}$$ 5. **Simplify the fraction:** $$t = \frac{\cancel{-240}}{\cancel{-60}} = 4$$ 6. **Interpretation:** The x-intercept $$t = 4$$ means that after 4 hours of driving, Stella will be 0 miles away from City A, i.e., she will have arrived at City A. **Final answer:** The x-intercept is $$4$$, which represents the time in hours when Stella reaches City A.