Question

Find the roots of quadratic equation $x^2+4x+5=0$ by using the quadratic formula.

Answer 1

The quadratic formula is $x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

Here $a=1,b=4,c=5$

$x=\frac{-4\pm \sqrt{4^2-4\left(1\right)\left(5\right)}}{2}$

$x=\frac{-4\pm \sqrt{-4}}{2}x=-2\pm i$