5b(3b-8)=0

Solution for 5b(3b-8)=0 equation:

5b(3b-8)=0

We multiply parentheses

15b^2-40b=0

a = 15; b = -40; c = 0;
Δ = b2-4ac
Δ = -402-4·15·0
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-40)-40}{2*15}=\frac{0}{30}
=0
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-40)+40}{2*15}=\frac{80}{30}
=2+2/3
$