y2-2y-8000=0

Solution for y2-2y-8000=0 equation:

y2-2y-8000=0

We add all the numbers together, and all the variables

y^2-2y-8000=0

a = 1; b = -2; c = -8000;
Δ = b2-4ac
Δ = -22-4·1·(-8000)
Δ = 32004
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{32004}=\sqrt{36*889}=\sqrt{36}*\sqrt{889}=6\sqrt{889}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-6\sqrt{889}}{2*1}=\frac{2-6\sqrt{889}}{2}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+6\sqrt{889}}{2*1}=\frac{2+6\sqrt{889}}{2}
$