x^2-9x-1800=0

Solution for x^2-9x-1800=0 equation:

x^2-9x-1800=0

a = 1; b = -9; c = -1800;
Δ = b2-4ac
Δ = -92-4·1·(-1800)
Δ = 7281
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:

$\sqrt{\Delta}=\sqrt{7281}=\sqrt{9*809}=\sqrt{9}*\sqrt{809}=3\sqrt{809}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-3\sqrt{809}}{2*1}=\frac{9-3\sqrt{809}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+3\sqrt{809}}{2*1}=\frac{9+3\sqrt{809}}{2}
$