100x^2+800x-1200=0

Solution for 100x^2+800x-1200=0 equation:

100x^2+800x-1200=0

a = 100; b = 800; c = -1200;
Δ = b2-4ac
Δ = 8002-4·100·(-1200)
Δ = 1120000
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:

$\sqrt{\Delta}=\sqrt{1120000}=\sqrt{160000*7}=\sqrt{160000}*\sqrt{7}=400\sqrt{7}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(800)-400\sqrt{7}}{2*100}=\frac{-800-400\sqrt{7}}{200}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(800)+400\sqrt{7}}{2*100}=\frac{-800+400\sqrt{7}}{200}
$