18x^2-8x-216=0

Solution for 18x^2-8x-216=0 equation:

18x^2-8x-216=0

a = 18; b = -8; c = -216;
Δ = b2-4ac
Δ = -82-4·18·(-216)
Δ = 15616
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:

$\sqrt{\Delta}=\sqrt{15616}=\sqrt{256*61}=\sqrt{256}*\sqrt{61}=16\sqrt{61}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-16\sqrt{61}}{2*18}=\frac{8-16\sqrt{61}}{36}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+16\sqrt{61}}{2*18}=\frac{8+16\sqrt{61}}{36}
$