To graph a line, we must find to points that belongs to it.
For this, first we can find the line equation in the slope intercept form y = ax + b
We know that a = 1 and, when x = 1, y = 4. Then we have:
Therefore, the line equation is:
For x = 0, we have y = 3.Therefore, we just need to draw a line passing through the points (0,3) and (1,4) as show in the figure below: