z^2-0.4z-0.29=0

Solution for z^2-0.4z-0.29=0 equation:

z^2-0.4z-0.29=0

a = 1; b = -0.4; c = -0.29;
Δ = b2-4ac
Δ = -0.42-4·1·(-0.29)
Δ = 1.32
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{-(-0.4)-\sqrt{1.32}}{2*1}=\frac{0.4-\sqrt{1.32}}{2}
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.4)+\sqrt{1.32}}{2*1}=\frac{0.4+\sqrt{1.32}}{2}
$