20c^2-20c=0

Solution for 20c^2-20c=0 equation:

20c^2-20c=0

a = 20; b = -20; c = 0;
Δ = b2-4ac
Δ = -202-4·20·0
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-20}{2*20}=\frac{0}{40}
=0
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+20}{2*20}=\frac{40}{40}
=1
$