1. **State the problem:** We need to write an equation in point-slope form to find the total distance $y$ Geoff travels after $x$ hours, given that Geoff paddles at an average speed of 3.5 miles per hour and after 5 hours has traveled 18 miles. 2. **Recall the point-slope form formula:** The point-slope form of a line is given by: $$y - y_1 = m(x - x_1)$$ where $m$ is the slope (rate of change), and $(x_1, y_1)$ is a point on the line. 3. **Identify the slope $m$:** The slope is the speed, which is 3.5 miles per hour. 4. **Identify the point $(x_1, y_1)$:** From the problem, after 5 hours ($x_1=5$), Geoff has traveled 18 miles ($y_1=18$). 5. **Write the equation:** Substitute $m=3.5$, $x_1=5$, and $y_1=18$ into the point-slope form: $$y - 18 = 3.5(x - 5)$$ This equation models the total distance $y$ traveled after $x$ hours. **Final answer:** $$y - 18 = 3.5(x - 5)$$