4(c-1)c=5

Solution for 4(c-1)c=5 equation:

4(c-1)c=5

We move all terms to the left:

4(c-1)c-(5)=0

We multiply parentheses

4c^2-4c-5=0

a = 4; b = -4; c = -5;
Δ = b2-4ac
Δ = -42-4·4·(-5)
Δ = 96
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{96}=\sqrt{16*6}=\sqrt{16}*\sqrt{6}=4\sqrt{6}$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4)-4\sqrt{6}}{2*4}=\frac{4-4\sqrt{6}}{8}
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4)+4\sqrt{6}}{2*4}=\frac{4+4\sqrt{6}}{8}
$