Consider the following relations :

$(1) \,\,\,A - B = A - (A \cap B)$

$(2) \,\,\,A = (A \cap B) \cup (A - B)$

$(3) \,\,\,A - (B \cup C) = (A - B) \cup (A - C)$

which of these is/are correct

Let $A=\{2,4,6,8\}$ and $B=\{6,8,10,12\} .$ Find $A \cup B$

If ${N_a} = [an:n \in N\} ,$ then ${N_5} \cap {N_7} = $

If $A  \cap B = B$, then

Show that the following four conditions are equivalent:

$(i)A \subset B\,\,\,({\rm{ ii }})A - B = \phi \quad (iii)A \cup B = B\quad (iv)A \cap B = A$

State whether each of the following statement is true or false. Justify you answer.

$\{2,6,10,14\}$ and $\{3,7,11,15\}$ are disjoint sets.