1. The problem asks to find the slope of the line given by the equation $y = 5x + 4$. 2. Recall that 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. In the equation $y = 5x + 4$, the coefficient of $x$ is $5$, so the slope $m = 5$. 4. Therefore, the slope of the line is $5$. Final answer: $\boxed{5}$