x^2+400x-9600=0

Solution for x^2+400x-9600=0 equation:

x^2+400x-9600=0

a = 1; b = 400; c = -9600;
Δ = b2-4ac
Δ = 4002-4·1·(-9600)
Δ = 198400
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:

$\sqrt{\Delta}=\sqrt{198400}=\sqrt{6400*31}=\sqrt{6400}*\sqrt{31}=80\sqrt{31}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(400)-80\sqrt{31}}{2*1}=\frac{-400-80\sqrt{31}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(400)+80\sqrt{31}}{2*1}=\frac{-400+80\sqrt{31}}{2}
$