X^2+400x-16000=0

Solution for X^2+400x-16000=0 equation:

X^2+400X-16000=0

a = 1; b = 400; c = -16000;
Δ = b2-4ac
Δ = 4002-4·1·(-16000)
Δ = 224000
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:

$\sqrt{\Delta}=\sqrt{224000}=\sqrt{6400*35}=\sqrt{6400}*\sqrt{35}=80\sqrt{35}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(400)-80\sqrt{35}}{2*1}=\frac{-400-80\sqrt{35}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(400)+80\sqrt{35}}{2*1}=\frac{-400+80\sqrt{35}}{2}
$