x-intercept is point (-8,0).
slope = rise/run = change in y/change in x
For slope = 0.5, change in y/change in x = 0.5 = 1/2.
So if you increase y by 1, you'll increase x by 2.
So starting with x-intercept, another point would be: (-8+2,0+1) = (-6,1).
Now you can draw a line between the two points.