x^2-15x-18000=0

Solution for x^2-15x-18000=0 equation:

x^2-15x-18000=0

a = 1; b = -15; c = -18000;
Δ = b2-4ac
Δ = -152-4·1·(-18000)
Δ = 72225
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:

$\sqrt{\Delta}=\sqrt{72225}=\sqrt{225*321}=\sqrt{225}*\sqrt{321}=15\sqrt{321}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-15\sqrt{321}}{2*1}=\frac{15-15\sqrt{321}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+15\sqrt{321}}{2*1}=\frac{15+15\sqrt{321}}{2}
$