Ao+Bo+Co+D=(AB^(')+A^(')B)o+(CD^(')+C^(')D)
=(AB^(')+A^(')B)(CD+C^(')D^('))+(AB+A^(')B^('))(CD^(')+C^(')D)
=Sigma (1,2,4,7,8,11,13,14)
( I couldn't understand how can i draw the Karnough map in this question)
= (AB' + A'B)(CD + C'D') + (AB + A'B')(CD' + C'D
=2(1,2,4,7,8,11,13,14)