Write the following as intervals: $\{x : x \in \mathbb{R}, 0 \le x < 7\}$

The set $A = \{ x : x \ne x \}$ represents:

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

Find the union of each of the following pairs of sets:
$A = \{1, 2, 3\}, B = \varnothing$

In the following,state whether $A = B$ or not:
$A = \{ x: x \text{ is a multiple of } 10 \}$
$B = \{ 10, 15, 20, 25, 30, \ldots \}$

Examine whether the following statement is true or false:
$\{x : x \text{ is an even natural number less than } 6\} \subset \{x : x \text{ is a natural number which divides } 36\}$