The expression is as under:
ABC + A'B +ABC'

 

Hi 12345,
Welcome to AAC.
As this is homework, we need to see your best attempt at answering, then we can help.
E

 

ABC + A'B +ABC'

Because this is homework I won't give you the answer, but this should get you started...
ABC + A'B + ABC'
ABC + ABC' + A'B
AB(C + C') + A'B
...

Hope that helps

 

If you need to show a derivation, then use Boolean algebra. If you just need the answer, then use a Karnaugh map. Note: A K-map is just a method to use the fact that boolean A+A' = 1.