What's the answer to this math problem?

What is the rate for one gallon of gasoline

Aline has a slope of . which ordered pairs could be points on a parallel line? check all that apply. (-8, 8) and (2, 2) (-5, -1) and (0, 2) (-3, 6) and (6, -9) (-2, 1) and (3,-2) (0, 2) and (5,5)

What is the slope of the line? a. -5/2 b.2/5 c. 5/2 d.7/2