x^2-13x-285=0

Solution for x^2-13x-285=0 equation:

x^2-13x-285=0

a = 1; b = -13; c = -285;
Δ = b2-4ac
Δ = -132-4·1·(-285)
Δ = 1309
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{-(-13)-\sqrt{1309}}{2*1}=\frac{13-\sqrt{1309}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-13)+\sqrt{1309}}{2*1}=\frac{13+\sqrt{1309}}{2}
$