I am attempting to teach myself/re-learn some basic digital logic design. As part of this, I am currently reading a chapter about boolean algebra. There are two problems which I have the solution to, but I cannot understand what reduction was done to achieve the solutions. Using a k map, I can deduce the same final answers, but I want to understand algebraically what I am missing.

Problem 1:Y=('A'B'C)+('AB'C)+(A'B'C)+A'BC)+(ABC)

Problem 2:Y=('A'BC)+('AB'C)+('ABC)+(A'BC)+(ABC)

I can get problem one down to

Y=('A'C)+(A'B)+(ABC)

and problem two down to

Y=AC+('AB+)+('A'BC)

However, the solutions I have say problem one should end up being

Y=('A'C)+(A'B)+(AC)

and problem two should end up being

Y=C+('AB)

Could someone please explain to me how I get from the point I am at now to the final solution? I feel that I must be missing some pretty obvious rules, but I cannot figure out what. Thanks for the help!