Here it is:
(ab + ab' + a'b)'\n= (ab)'(ab')'(a'b)'\n= (a' + b')(a' + b)(a + b')\n= (a' + b'b)(a + b'\n= a'(a + b')\n= a'a + a'b'\n= a'b'Is this correct? I'm having a hard time in that when I take different approaches to the problem, I'm getting different answers which don't seem compatible.