Answer:
y - 3 = (1/2)(x - 1)
Explanation:
First find the slope of the line through these two points. As we move from (1, 3) to (5, 1), x (the run) increases by 4 and y (the rise) decreases by 2. Thus, the slope is m = rise / run = 2/4, or m = 1/2.
Working from the given point (1, 3), we have:
y - 3 = (1/2)(x - 1)