Question

If $R=\{x:x^2=7\},S=\{x:x+4=4\}$ and $T=\{x:x^2+2=8\}$, then which of the following is correct?

• A. $R$ and $T$ are equal sets.
• B. $R$ and $S$ are equal sets.
• C. $S$ and $T$ are equal sets.
• D. None of them are equal sets.

Answer 1

The correct option is D None of them are equal sets.

$R=\{x:x^2=7\}\Rightarrow R=\{-\sqrt{7},\sqrt{7}\}S=\{x:x+4=4\}\Rightarrow S=\left\{0\right\}$
$T=\{x:x^2+2=8\}\Rightarrow T=\{-\sqrt{6},\sqrt{6}\}$

Hence, none of them are equal sets.