The slope of the line in the graph is 1/2
How to find the slope of the line?
If a line passes through two points (x₁, y₁) and (x₂, y₂), then the slope of the line is:
a = (y₂ - y₁)/(x₂ - x₁)
Here we can see the points (1, 1) and (3, 2) in the graph, so the slope of this line will be:
a = (2 - 1)/(3 - 1)
a = 1/2