3(v+5)(-v-4)=0

Solution for 3(v+5)(-v-4)=0 equation:

3(v+5)(-v-4)=0

We add all the numbers together, and all the variables

3(v+5)(-1v-4)=0

We multiply parentheses ..

3(-1v^2-4v-5v-20)=0

We multiply parentheses

-3v^2-12v-15v-60=0

We add all the numbers together, and all the variables

-3v^2-27v-60=0

a = -3; b = -27; c = -60;
Δ = b2-4ac
Δ = -272-4·(-3)·(-60)
Δ = 9
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{9}=3$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-27)-3}{2*-3}=\frac{24}{-6}
=-4
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-27)+3}{2*-3}=\frac{30}{-6}
=-5
$