Answer:
y = 3/4x +4
Explanation:
From point A to point B, you show a rise of 3 units and a run of 4 units. (The rise is the difference in height of the first two squares; the run is the side length of the first square.) The ratio rise/run = 3/4 is the slope of the line you want.
The upper-left corner of the first square is the y-intercept of the line (4). So, in slope-intercept form, the equation of the dotted line is ...
y = mx + b . . . . . m = slope; b = y-intercept
y = 3/4x + 4