0.62z^2-0.62z-0.16=0

Solution for 0.62z^2-0.62z-0.16=0 equation:

0.62z^2-0.62z-0.16=0

a = 0.62; b = -0.62; c = -0.16;
Δ = b2-4ac
Δ = -0.622-4·0.62·(-0.16)
Δ = 0.7812
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-0.62)-\sqrt{0.7812}}{2*0.62}=\frac{0.62-\sqrt{0.7812}}{1.24}
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.62)+\sqrt{0.7812}}{2*0.62}=\frac{0.62+\sqrt{0.7812}}{1.24}
$