Question

são raízes da equação x2 +324=0
a)18+3i
b)18+i e 18-i
c)-18 e 18i
d)8i e -8i

Answer 1

$x^2+324 = 0\\\\ x^2=-324\\\\ x = 18i\ ou \ -18i$

Answer 2

$x^2+324=0\\ \\ x^2=-324\\ \\ x= \pm \sqrt{-324}\\ \\ x=\pm \sqrt{324.(-1)}\\ \\ x= \pm \sqrt{324}.\sqrt{-1}\\ \\ \boxed{x= \pm 18i}$