0.04z^2+0.04z-0.07=0

Solution for 0.04z^2+0.04z-0.07=0 equation:

0.04z^2+0.04z-0.07=0

a = 0.04; b = 0.04; c = -0.07;
Δ = b2-4ac
Δ = 0.042-4·0.04·(-0.07)
Δ = 0.0128
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{-(0.04)-\sqrt{0.0128}}{2*0.04}=\frac{-0.04-\sqrt{0.0128}}{0.08}
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.04)+\sqrt{0.0128}}{2*0.04}=\frac{-0.04+\sqrt{0.0128}}{0.08}
$