Simplify $ab' + ( a'+b )c$

Question

Boolean algebra How to solve it. I am stuck after first step which is $ab' +(ab')'c$. After that I couldn't get the exact answer.

The answer is $ab' + c.$

Answer 1

HINT

It is $k+k'c=k(c+c')+k'c,$ where $k=ab'.$ Can you finish it now?

Answer 2

$$ab'+(ab')'c = (ab'+(ab')')(ab'+c)=1(ab'+c)=ab'+c$$