-30v-25=-9v^2

Solution for -30v-25=-9v^2 equation:

-30v-25=-9v^2

We move all terms to the left:

-30v-25-(-9v^2)=0

We get rid of parentheses

9v^2-30v-25=0

a = 9; b = -30; c = -25;
Δ = b2-4ac
Δ = -302-4·9·(-25)
Δ = 1800
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:

$\sqrt{\Delta}=\sqrt{1800}=\sqrt{900*2}=\sqrt{900}*\sqrt{2}=30\sqrt{2}$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-30\sqrt{2}}{2*9}=\frac{30-30\sqrt{2}}{18}
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+30\sqrt{2}}{2*9}=\frac{30+30\sqrt{2}}{18}
$