5v(v+9)=0

Solution for 5v(v+9)=0 equation:

5v(v+9)=0

We multiply parentheses

5v^2+45v=0

a = 5; b = 45; c = 0;
Δ = b2-4ac
Δ = 452-4·5·0
Δ = 2025
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2025}=45$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(45)-45}{2*5}=\frac{-90}{10}
=-9
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(45)+45}{2*5}=\frac{0}{10}
=0
$