A slope of 3 means that y increases by 3 when x increases by 1.
The second point (2, k) has an x-value (2) that is 1 more than the x-value (1) of the first point (1, 5). This means the y-value (k) of the second point (2, k) will be 3 more than the y-value (5) of the first point (1, 5).
