# How do you solve the quadratic x^2+4=0 using any method?

Aug 26, 2016

$x = - 2 i$ or $x = 2 i$

#### Explanation:

${x}^{2} + 4 = 0$

$\Leftrightarrow {x}^{2} - \left(- 4\right) = 0$ or

as ${i}^{2} = - 1$ and hence

${x}^{2} - {\left(2 i\right)}^{2} = 0$ or

$\left(x + 2 i\right) \left(x - 2 i\right) = 0$ or

$x + 2 i = 0$ or$x - 2 i = 0$

i.e. $x = - 2 i$ or $x = 2 i$