∠ABF and ∠CBE are vertical angles
3x + 25 + 7x - 19 = 10x - 6
Set them equal to each other
∠ABF = ∠CBE
6x + 26 = 10x - 6
Isolate the x. Subtract 6x from both sides and add 6 to both sides
6x (-6x) + 26 (+6) = 10x (-6x) - 6 (+6)
26 + 6 = 10x - 6x
Simplify
32 = 4x
Divide 4 from both sides
32/4 = 4x/4
x = 32/4
x = 8
m∠ABF = 6x + 26
Plug in 8 for x
6(8) + 26 = m∠ABF
48 + 26 = m∠ABF
m∠ABF = 74°
74° is your answer for m∠F
hope this helps