5v^2-30v=-40

Solution for 5v^2-30v=-40 equation:

5v^2-30v=-40

We move all terms to the left:

5v^2-30v-(-40)=0

We add all the numbers together, and all the variables

5v^2-30v+40=0

a = 5; b = -30; c = +40;
Δ = b2-4ac
Δ = -302-4·5·40
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-10}{2*5}=\frac{20}{10}
=2
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+10}{2*5}=\frac{40}{10}
=4
$