If $A = \{x \in R : x^2 - 5|x| + 6 = 0\}$,then find $n(A)$.

Let $A = \{1, 2, \{3, 4\}, 5\}$. Which of the following statements is incorrect and why? $\{ \{ 3, 4\} \} \subset A$

State whether the following statement is true or false. Justify your answer.
${2, 6, 10}$ and ${3, 7, 11}$ are disjoint sets.

In the following,state whether $A = B$ or not:
$A = \{2, 4, 6, 8, 10\}$; $B = \{x : x \text{ is a positive even integer and } x \le 10\}$

Two dice are thrown. The events $A$,$B$,and $C$ are as follows:
$A$: getting an even number on the first die.
$B$: getting an odd number on the first die.
$C$: getting the sum of the numbers on the dice $\leq 5$.
State true or false: (give reason for your answer)
Statement: $A$ and $B^{\prime}$ are mutually exclusive.

Write the following set in the set-builder form: $\{ 2, 4, 6, \dots \}$