If m abf=7b-24 and m Abe = 2b what is m EBF

As m abe = 2b, it seems like abe is the whole angle and abf and ebf are the parts of angle abe, then

m abe = m abf + m ebf

and we have to find m ebf so,

m ebf = m abe - m abf

now putting the values of angles abe and abf, we get

m ebf = 2b - (7b - 24)

m ebf = 2b - 7b + 24

mebf = - 5b + 24