-3n(5n-2)=0

Solution for -3n(5n-2)=0 equation:

-3n(5n-2)=0

We multiply parentheses

-15n^2+6n=0

a = -15; b = 6; c = 0;
Δ = b2-4ac
Δ = 62-4·(-15)·0
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-6}{2*-15}=\frac{-12}{-30}
=2/5
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+6}{2*-15}=\frac{0}{-30}
=0
$