Answer
$l_{1}$
Work Step by Step
For a line with a positive slope, as m increases, the line becomes steeper (as shown on pg. 158). In other words, for 2 lines with positive slopes, the steeper line will have a greater slope. By looking at the graph, we can tell that $l_{1}$ is steeper than $l_{2}$, so $l_{1}$ must have a greater slope.
