2v(v+4)=15

Solution for 2v(v+4)=15 equation:

2v(v+4)=15

We move all terms to the left:

2v(v+4)-(15)=0

We multiply parentheses

2v^2+8v-15=0

a = 2; b = 8; c = -15;
Δ = b2-4ac
Δ = 82-4·2·(-15)
Δ = 184
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:

$\sqrt{\Delta}=\sqrt{184}=\sqrt{4*46}=\sqrt{4}*\sqrt{46}=2\sqrt{46}$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-2\sqrt{46}}{2*2}=\frac{-8-2\sqrt{46}}{4}
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+2\sqrt{46}}{2*2}=\frac{-8+2\sqrt{46}}{4}
$