V=6x^2-30x-36

Solution for V=6x^2-30x-36 equation:

=6V^2-30V-36

We move all terms to the left:

-(6V^2-30V-36)=0

We get rid of parentheses

-6V^2+30V+36=0

a = -6; b = 30; c = +36;
Δ = b2-4ac
Δ = 302-4·(-6)·36
Δ = 1764
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$V_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$V_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1764}=42$
$V_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-42}{2*-6}=\frac{-72}{-12}
=+6
$
$V_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+42}{2*-6}=\frac{12}{-12}
=-1
$