Hi I'm trying to simplify this expression but I have no idea where to start (image attached):

 

Look into DeMorgan's Theorems in the on line textbook

 

I think it simplifies to (A + B)(A' + B')

 

Sorry, the actual question was prove that it is equal to A.B' + B.A'. Yeah I'll check out that link thanks guys

 

I think I have done it, but can you check my working out (I did it on paint because some of it is quite messy):

 

XYZ,

You can download the program featured on the link below, and find the minterms of just about any logic expression you care to key in. From the minterms, you can simplify the expression with a Karnaugh map if necessary. It won't show you the derivation of the minterms, but you can use it to check your worked out answer. If the minterms of your simplification do not match the original problem, then your solution is wrong.

Ratch

http://forum.allaboutcircuits.com/showthread.php?t=22347&highlight=logic+lovers