Question

Which of the following is an empty set?

• A.
• B.
• C.
• D.

Answer 1

Answer: (B), (C)

The correct options are
B

C

$x^2$ + 1 = 0 $⟹$ $x^2$ = -1

similarly
$x^2$ + 9 = 0 $⟹$ $x^2$ = -9

Given x is a real number and from the above two equations, we can conclude x is not real. (According to the question)

Therefore No value of x is possible.