Solve using the quadratic formula
hello berserk,
i am not sure if you have learn complex number yet but,
$\displaystyle \sqrt {-1} = \pm i$
and
$\displaystyle \sqrt {-25}=
\sqrt {-5^2} = \pm 5i
$
therefore say,
$\displaystyle x=\sqrt{-25} $
then,
$\displaystyle
x=\pm 5i
$