-2v^2=15v+25

Solution for -2v^2=15v+25 equation:

-2v^2=15v+25

We move all terms to the left:

-2v^2-(15v+25)=0

We get rid of parentheses

-2v^2-15v-25=0

a = -2; b = -15; c = -25;
Δ = b2-4ac
Δ = -152-4·(-2)·(-25)
Δ = 25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25}=5$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-5}{2*-2}=\frac{10}{-4}
=-2+1/2
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+5}{2*-2}=\frac{20}{-4}
=-5
$