7c^2+27c-4=0

Solution for 7c^2+27c-4=0 equation:

7c^2+27c-4=0

a = 7; b = 27; c = -4;
Δ = b2-4ac
Δ = 272-4·7·(-4)
Δ = 841
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{841}=29$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(27)-29}{2*7}=\frac{-56}{14}
=-4
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(27)+29}{2*7}=\frac{2}{14}
=1/7
$