(8z+4)5z+10)=0

Solution for (8z+4)5z+10)=0 equation:

(8z+4)5z+10)=0

We add all the numbers together, and all the variables

(8z+4)5z=0

We multiply parentheses

40z^2+20z=0

a = 40; b = 20; c = 0;
Δ = b2-4ac
Δ = 202-4·40·0
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-20}{2*40}=\frac{-40}{80}
=-1/2
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+20}{2*40}=\frac{0}{80}
=0
$