A) Since the lines are parallel, those angles are corresponding angles, therefore:
2x + 10 = 3x - 15
10 = x - 15
x = 25
B) Angle EFJ and angle BFE are linear pairs, and they add up to 180°, so:
2(25) + 10 + Angle EFJ = 180
60 + Angle EFJ = 180
Angle EFJ = 120