18x^2-39x-84=0

Solution for 18x^2-39x-84=0 equation:

18x^2-39x-84=0

a = 18; b = -39; c = -84;
Δ = b2-4ac
Δ = -392-4·18·(-84)
Δ = 7569
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{7569}=87$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-39)-87}{2*18}=\frac{-48}{36}
=-1+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-39)+87}{2*18}=\frac{126}{36}
=3+1/2
$