Slope and Y-Intercept Calculation

Consider the equation of a line, which is expressed in slope-intercept form as:

$$y = mx + b$$

where $m$ represents the slope, and $b$ represents the y-intercept.

A line passes through the points (3, 7) and (7, 15).

First, calculate the slope $m$ of this line. Then, using the slope and one of the points, find the y-intercept $b$. Finally, input the value of $b$ in the grid below.