X2-80x-1500=0

Solution for X2-80x-1500=0 equation:

X2-80X-1500=0

We add all the numbers together, and all the variables

X^2-80X-1500=0

a = 1; b = -80; c = -1500;
Δ = b2-4ac
Δ = -802-4·1·(-1500)
Δ = 12400
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:

$\sqrt{\Delta}=\sqrt{12400}=\sqrt{400*31}=\sqrt{400}*\sqrt{31}=20\sqrt{31}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-80)-20\sqrt{31}}{2*1}=\frac{80-20\sqrt{31}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-80)+20\sqrt{31}}{2*1}=\frac{80+20\sqrt{31}}{2}
$