I'm trying to simplify the expression: A'BC + A'BD' + AB' + AC + ABC + ACD
I got to the expression: BC + AC + A'BD' + AB'
I know this expression is equvalant to the one above because I verified using truth tables.
The simplified expression, according to online calculators is: BC + A'BD' + AB'
How do I continue with my simplification?
This is an application of the Consensus Theorem:
$xy + y'z = xy + y'z + xz$
Applied to your case, we thus have that:
$AB' + BC + AC = AB' +BC$
So, if you have the Consensus Theorem in your arsenal, you can just do in 1 step:
$BC + AC + A'BD' + AB' \overset{Consensus}{=}$
$BC + A'BD'+AB'$
If you can't use Consensus, but you do have Adjacency ($xy +xy'=x$) and Absorption ($p + pq =p$), then you can do:
$BC + AC + A'BD' + AB' \overset{Adjacency}{=}$
$BC + ABC + AB'C + A'BD' + AB' \overset{Absorption \ \times \ 2}{=}$
$BC+ A'BD' + AB'$
And if you don't have those either, do what tranceloction does in the other answer.