Step-by-step explanation:
"If the sum of 2 angles is 180°, then each is the supplementary angle of the other".
Q16- 3/2 (slope = rise over run) Lmk if you need a further explanation
If the points are collinear, then that means they lie on the same line when connected to each other. In order to prove this, the distances between the points must sum up to the length of the line.
AB + BC = AC
7 + 4 ? 9
11 ≠ 9
Since they do not sum up, therefore, the points are not collinear.