0.22z^2-0.15-0.63z=0

Solution for 0.22z^2-0.15-0.63z=0 equation:

0.22z^2-0.15-0.63z=0

a = 0.22; b = -0.63; c = -0.15;
Δ = b2-4ac
Δ = -0.632-4·0.22·(-0.15)
Δ = 0.5289
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{-(-0.63)-\sqrt{0.5289}}{2*0.22}=\frac{0.63-\sqrt{0.5289}}{0.44}
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.63)+\sqrt{0.5289}}{2*0.22}=\frac{0.63+\sqrt{0.5289}}{0.44}
$