An algebra problem by Guillermo Templado

For a quadratic equation $ax^2 + bx + c$ , we have the sum of roots as $-\frac{b}{a}$ . In this problem, we have $a=1$ and $b=0$ , Thus $-\frac{b}{a}$ = $-\frac{0}{1}$ = $\boxed 0$

The roots are $i$ and $-i$ , which sum to $\boxed{0}$