X^2-21.5x-10000=0

Solution for X^2-21.5x-10000=0 equation:

X^2-21.5X-10000=0

a = 1; b = -21.5; c = -10000;
Δ = b2-4ac
Δ = -21.52-4·1·(-10000)
Δ = 40462.25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-21.5)-\sqrt{40462.25}}{2*1}=\frac{21.5-\sqrt{40462.25}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-21.5)+\sqrt{40462.25}}{2*1}=\frac{21.5+\sqrt{40462.25}}{2}
$