Answer:
75
Step-by-step explanation:
The sum of two interior angles in a triangle is equal to an exterior angle that is supplementary to the third interior angle:
3x + 2 + 55 = 13x - 3 add like terms
3x + 57 = 13x - 3 export like terms to the same side
57 + 3 = 13x - 3x
60 = 10x divide both sides by 10
6 = x to find angle FAB replace x with 6
13*6 - 3 = 75
