Two angles in a triangle add up to 125 degrees what is the size of the third angles

On an airplane there are two seats on the left side and three seats on the right side there are 90 seats o the right side of the plane

A, b, c, and d have the coordinates (-8, 1), (-2, 4), (-3, -1), and (-6, 5), respectively. which sentence about the points is true? a. a, b, c, and d lie on the same line. b. and are perpendicular lines. c. and are parallel lines. d. and are intersecting lines but are not perpendicular. e. and are parallel lines.

How do you use the elimination method for this question? explain, because i really want to understand!