15c^2-7c-12=0

Solution for 15c^2-7c-12=0 equation:

15c^2-7c-12=0

a = 15; b = -7; c = -12;
Δ = b2-4ac
Δ = -72-4·15·(-12)
Δ = 769
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-\sqrt{769}}{2*15}=\frac{7-\sqrt{769}}{30}
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+\sqrt{769}}{2*15}=\frac{7+\sqrt{769}}{30}
$