the easiest way to determine the equation of this line is to
1) determine the y-intercept, and
2) use the given slope to come up with another point on the line.
Looking at the graph, you can easily see that the graph crosses the y-axis at (0,2). Thus, the y-intercept is 2.
Now let's determine the slope of this line:
Begin at the point (-4,0) (which happens to be the x-intercept).
Move 4 units from there to the right. How many units UP must you then travel to reach the graph? call this "m."
Then the slope is m/4.
Then the equation of the line is y = mx + b, or
y=(1/2)x + 2 or y = x/2 + 2