14.

Substitute (2,9) first, a 2 = 9, a = 3 or -3 (rounded) [indicating that a 2 represents the square of a].

2.？ F (x) = 3 x，？ So f (-1) = 3 (-1) =1/3.

I wish you progress in your study. Better ask together in the future. Maybe more people will help you.