X2+100x-1200=0

Solution for X2+100x-1200=0 equation:

X2+100X-1200=0

We add all the numbers together, and all the variables

X^2+100X-1200=0

a = 1; b = 100; c = -1200;
Δ = b2-4ac
Δ = 1002-4·1·(-1200)
Δ = 14800
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:

$\sqrt{\Delta}=\sqrt{14800}=\sqrt{400*37}=\sqrt{400}*\sqrt{37}=20\sqrt{37}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(100)-20\sqrt{37}}{2*1}=\frac{-100-20\sqrt{37}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(100)+20\sqrt{37}}{2*1}=\frac{-100+20\sqrt{37}}{2}
$