5c^2+5c-30=0

Solution for 5c^2+5c-30=0 equation:

5c^2+5c-30=0

a = 5; b = 5; c = -30;
Δ = b2-4ac
Δ = 52-4·5·(-30)
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-25}{2*5}=\frac{-30}{10}
=-3
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+25}{2*5}=\frac{20}{10}
=2
$