3n^2=-15n

Solution for 3n^2=-15n equation:

3n^2=-15n

We move all terms to the left:

3n^2-(-15n)=0

We get rid of parentheses

3n^2+15n=0

a = 3; b = 15; c = 0;
Δ = b2-4ac
Δ = 152-4·3·0
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-15}{2*3}=\frac{-30}{6}
=-5
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+15}{2*3}=\frac{0}{6}
=0
$