find the value of x for which the expression in above is equal zero

Answer 1

if { 1,2,3,4,5,6,7,8,9,10,11,12,}
A={4,6,12,}
B={2,4,9,}
find A . a
B . anb
C. (AVB)

Answer 2

you have garbled both questions, but it is clear that
A∩B = {4}
AUB = {2,4,6,9,12}
Maybe you can do the rest, or at least make it clear what you want.