Question

The solution set of $x^2+1<10$ is

• A. $[-3,3]$
• B. $(-3,3)$
• C. $R$
• D. $\varphi \text{(empty set)}$

Answer 1

The correct option is B $(-3,3)$

$x^2+1<10\Rightarrow x^2-9<0\Rightarrow (x+3)(x-3)<0$


$\therefore x\in (-3,3)$