Answer:
Assuming 1,6 is y2 and x2, the answer is 1,-2 = -0.5
Explanation:
1. Grab 1,6 as it is the second point and invert it into 6,1
2. Invert the first point into 5,3.
3. Subtract (6 - 5) / (1 - 3). The result is 1/-2.
4. Divide 1 by -2.
Answer should be -0.5