Answer:
(14x+6)°
Step-by-step explanation:
Given m∠FBC = (10x –9)° and m∠CBE = (4x + 15), the following expression will be used to find m∠FBE
m∠FBE = m∠FBC+m∠BE
Substituting the given functions
m∠FBE = 10x-9 + 4x+15
collect like terms
m∠FBE = 10x+4x-9+15
m∠FBE = 14x + 6
Hence m∠FBE is (14x+6)°