2x^2-36x-255=0

Solution for 2x^2-36x-255=0 equation:

2x^2-36x-255=0

a = 2; b = -36; c = -255;
Δ = b2-4ac
Δ = -362-4·2·(-255)
Δ = 3336
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:

$\sqrt{\Delta}=\sqrt{3336}=\sqrt{4*834}=\sqrt{4}*\sqrt{834}=2\sqrt{834}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-36)-2\sqrt{834}}{2*2}=\frac{36-2\sqrt{834}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-36)+2\sqrt{834}}{2*2}=\frac{36+2\sqrt{834}}{4}
$