Answer:
m = 19/14 so the third point is (8, 19/7).
Step-by-step explanation:
If they are co-linear then the the slope will be equal.
The slopes of the lines are:
(difference in y coordinates) / (difference in corresponding x coordinates)
Slope between the first 2 points = (-3-1) / (-2-5) -4 / -7
= 4/7.
So if the 3 points are co-linear:
4/7 = (2m - -3) / (8 - -2)
4/7 = (2m + 3 / 10
7(2m + 3) = 40
14m + 21 = 40
14m = 19.
m = 19/14.