(x2+20x+99)=0

Solution for (x2+20x+99)=0 equation:

(x2+20x+99)=0

We add all the numbers together, and all the variables

(+x^2+20x+99)=0

We get rid of parentheses

x^2+20x+99=0

a = 1; b = 20; c = +99;
Δ = b2-4ac
Δ = 202-4·1·99
Δ = 4
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4}=2$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-2}{2*1}=\frac{-22}{2}
=-11
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+2}{2*1}=\frac{-18}{2}
=-9
$