The set $A = \{ x : x \in \mathbb{R}, x^2 = 16 \text{ and } 2x = 6 \}$ is equal to

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

State which of the following sets are finite or infinite:
$A = \{ x : x \in \mathbb{N} \text{ and } x \text{ is prime} \}$

State whether the following set is finite or infinite:
The set of lines which are parallel to the $x$-axis.

Let $P$ and $T$ be the subsets of the $xy$-plane defined by $P = \{(x, y) : x > 0, y > 0 \text{ and } x^2 + y^2 = 1\}$ and $T = \{(x, y) : x > 0, y > 0 \text{ and } x^8 + y^8 < 1\}$. Then, $P \cap T$ is

If $A = \{ x : x \text{ is a natural number} \}$,$B = \{ x : x \text{ is an even natural number} \}$,$C = \{ x : x \text{ is an odd natural number} \}$,and $D = \{ x : x \text{ is a prime number} \}$,find $A \cap D$.