find the value of p if the points A (2,3) ,B (4,p) ,C (6,-3) are collinear

Question

find the value of p if the points A (2,3) ,B (4,p) ,C (6,-3) are collinear

Answer 1

In the x coordinates 4 is half way between 2 and 6.

Therefore the y coordinate, p, shall be half way between 3 and -3.

What is that?