X2+120x+2400=0

Solution for X2+120x+2400=0 equation:

X2+120X+2400=0

We add all the numbers together, and all the variables

X^2+120X+2400=0

a = 1; b = 120; c = +2400;
Δ = b2-4ac
Δ = 1202-4·1·2400
Δ = 4800
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{4800}=\sqrt{1600*3}=\sqrt{1600}*\sqrt{3}=40\sqrt{3}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(120)-40\sqrt{3}}{2*1}=\frac{-120-40\sqrt{3}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(120)+40\sqrt{3}}{2*1}=\frac{-120+40\sqrt{3}}{2}
$