12x^2+21x-108=0

Solution for 12x^2+21x-108=0 equation:

12x^2+21x-108=0

a = 12; b = 21; c = -108;
Δ = b2-4ac
Δ = 212-4·12·(-108)
Δ = 5625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5625}=75$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(21)-75}{2*12}=\frac{-96}{24}
=-4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+75}{2*12}=\frac{54}{24}
=2+1/4
$