X2+76x-1280=0

Solution for X2+76x-1280=0 equation:

X2+76X-1280=0

We add all the numbers together, and all the variables

X^2+76X-1280=0

a = 1; b = 76; c = -1280;
Δ = b2-4ac
Δ = 762-4·1·(-1280)
Δ = 10896
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:

$\sqrt{\Delta}=\sqrt{10896}=\sqrt{16*681}=\sqrt{16}*\sqrt{681}=4\sqrt{681}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(76)-4\sqrt{681}}{2*1}=\frac{-76-4\sqrt{681}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(76)+4\sqrt{681}}{2*1}=\frac{-76+4\sqrt{681}}{2}
$