Answer:
600 miles.
Explanation:
So basically we can write both plans as linear functions:
F(x) = $59.96+$0.14 . x
S(x) = $71.96+$0.12 . x
Where F(x) is the first plan, S(x) is the second one and X are the miles driven.
To know how many miles does Mai need to drive for the two plans to cost the same, we equalize both equations and isolate x.
F(x) = S (x)

Mai has to drive 600 miles for the two plans to cost the same-