X2+100x+900=0

Solution for X2+100x+900=0 equation:

X2+100X+900=0

We add all the numbers together, and all the variables

X^2+100X+900=0

a = 1; b = 100; c = +900;
Δ = b2-4ac
Δ = 1002-4·1·900
Δ = 6400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6400}=80$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(100)-80}{2*1}=\frac{-180}{2}
=-90
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(100)+80}{2*1}=\frac{-20}{2}
=-10
$