(4w+8)(5w-10)=0

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

(4w+8)(5w-10)=0

We multiply parentheses ..

(+20w^2-40w+40w-80)=0

We get rid of parentheses

20w^2-40w+40w-80=0

We add all the numbers together, and all the variables

20w^2-80=0

a = 20; b = 0; c = -80;
Δ = b2-4ac
Δ = 02-4·20·(-80)
Δ = 6400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6400}=80$
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-80}{2*20}=\frac{-80}{40}
=-2
$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+80}{2*20}=\frac{80}{40}
=2
$