Question

if a.b is 0 and b.c is 0 then what is a.c?

Answer 1

Let's build the truth table:

a b c& a.b b.c a.c
1 1 1 1 1 1
1 1 0 1 0 0
1 0 1 0 0 1
1 0 0 0 0 0
0 1 1 0 1 0
0 1 0 0 0 0
0 0 1 0 0 0
0 0 0 0 0 0

As we can see from this table, a.c can take both values (0 or 1) when a.b is 0 and b.c is 0.