Slope intercept form:
y = mx + b
where m is the slope and b is the y-intercept.
Look at your graph. The Y-Intercept is +4. Plug it into your equation:
y = mx + 4
Look at your graph. The slope is (rise/run) - find two whole points and (rise/run). Take (-1, 1) (p1) and (0,4) (p2). Rise up 3 and run right 1 from p1 to reach p2.
y = (3/1)x + 4
y = 3x + 4
