Question

what is the square root of -169

Answer 1

$\sqrt{-169} \to \boxed{ - /+ 13i}$

Answer 2

Square root -169
$= \sqrt{-169} = \sqrt{169}$ * $\sqrt{-1}$
                          =   13*i  = 13i.

Note square root of -1 is represented by i.

Square roots usually have two answers;  +/-
More correct answer =  +/- 13i