1. **State the problem:** We are given a linear pricing model for Juan's Taxicab Company with two points: (0, 4) and (10, 18). We need to find the equation of the line representing the total charges $y$ as a function of miles $x$. 2. **Formula used:** The equation of a line is given by: $$y = mx + b$$ where $m$ is the slope and $b$ is the y-intercept. 3. **Calculate the slope $m$:** The slope formula is: $$m = \frac{y_2 - y_1}{x_2 - x_1}$$ Using points $(0,4)$ and $(10,18)$: $$m = \frac{18 - 4}{10 - 0} = \frac{14}{10} = \frac{7}{5}$$ 4. **Find the y-intercept $b$:** Since the line passes through $(0,4)$, the y-intercept is: $$b = 4$$ 5. **Write the equation:** $$y = \frac{7}{5}x + 4$$ 6. **Interpretation:** The total charge increases by $\frac{7}{5}$ dollars per mile, starting at $4 when no miles are traveled. 7. **Camila's company charge:** Camila's company charges $0 more per mile than Juan's, so the slope is the same. **Final answer:** $$\boxed{y = \frac{7}{5}x + 4}$$