0=-10n-5n^2

Solution for 0=-10n-5n^2 equation:

0=-10n-5n^2

We move all terms to the left:

0-(-10n-5n^2)=0

We add all the numbers together, and all the variables

-(-10n-5n^2)=0

We get rid of parentheses

5n^2+10n=0

a = 5; b = 10; c = 0;
Δ = b2-4ac
Δ = 102-4·5·0
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-10}{2*5}=\frac{-20}{10}
=-2
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+10}{2*5}=\frac{0}{10}
=0
$