5w(4w-5)=0

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

5w(4w-5)=0

We multiply parentheses

20w^2-25w=0

a = 20; b = -25; c = 0;
Δ = b2-4ac
Δ = -252-4·20·0
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-25)-25}{2*20}=\frac{0}{40}
=0
$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+25}{2*20}=\frac{50}{40}
=1+1/4
$