1. **State the problem:** Find the equation of the blue line passing through points $(1,6)$ and $(3,10)$.\n\n2. **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.\n\n3. **Calculate the slope $m$:**\n$$m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{10 - 6}{3 - 1} = \frac{4}{2} = 2$$\n\n4. **Find the y-intercept $b$:** Use one point, for example $(1,6)$, and plug into $y = mx + b$:\n$$6 = 2 \times 1 + b \implies b = 6 - 2 = 4$$\n\n5. **Write the equation:**\n$$y = 2x + 4$$\n\nThis is the equation of the blue line.