-8=-4v+2v(v-8)

Solution for -8=-4v+2v(v-8) equation:

-8=-4v+2v(v-8)

We move all terms to the left:

-8-(-4v+2v(v-8))=0


We calculate terms in parentheses: -(-4v+2v(v-8)), so:

-4v+2v(v-8)

We multiply parentheses

2v^2-4v-16v

We add all the numbers together, and all the variables

2v^2-20v

Back to the equation:

-(2v^2-20v)


We get rid of parentheses

-2v^2+20v-8=0

a = -2; b = 20; c = -8;
Δ = b2-4ac
Δ = 202-4·(-2)·(-8)
Δ = 336
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{336}=\sqrt{16*21}=\sqrt{16}*\sqrt{21}=4\sqrt{21}$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-4\sqrt{21}}{2*-2}=\frac{-20-4\sqrt{21}}{-4}
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+4\sqrt{21}}{2*-2}=\frac{-20+4\sqrt{21}}{-4}
$