i am suppose to simplify this expression: A'B'C + A'BC' + AB'C' + ABC, i am suck at B'C + BC' + B'C' + BC. What do i do next??

 

You don't have the right to remove the variable A from the expression.
Are you familiar with Karnaugh maps? They are used to simplify Boolean expressions. Have a look here:
http://www.allaboutcircuits.com/vol_4/chpt_8/index.html

Alternatively, try to factor out the variable A, and then factor out B and B' from the four remaining terms.