1. **State the problem:** We need to find the equation of the blue line passing through points approximately (1, 2) and (2, 6). 2. **Formula used:** The equation of a line in slope-intercept form is $$y = mx + b$$ where $m$ is the slope and $b$ is the y-intercept. 3. **Calculate the slope $m$:** $$m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{6 - 2}{2 - 1} = \frac{4}{1} = 4$$ 4. **Find the y-intercept $b$:** Use one point, say (1, 2), and plug into $y = mx + b$: $$2 = 4 \times 1 + b \implies b = 2 - 4 = -2$$ 5. **Write the equation:** $$y = 4x - 2$$ 6. **Explanation:** The slope 4 means the line rises 4 units vertically for every 1 unit it moves horizontally. The y-intercept -2 means the line crosses the y-axis at (0, -2).