Opening the paper…
Let . Select all the true statements.
Let $A = \{1,\ 2,\ \{3,4\}\}$. Select all the true statements. Let $B = \{n \in \mathbb{Z}^+ : n \text{ is odd and } n^2 < 150\}$. How many elements does $B$ have? Consider $P=\{x\in\mathbb{Z}: x^2=4\}$, $Q=\{x\in\mathbb{Z}: |x|=2\}$, $R=\{x\in\mathbb{Z}: x^3-4x=0\}$ and $T=\{2\}$. Select all the true statements.