9n(2n-8)=0

Solution for 9n(2n-8)=0 equation:

9n(2n-8)=0

We multiply parentheses

18n^2-72n=0

a = 18; b = -72; c = 0;
Δ = b2-4ac
Δ = -722-4·18·0
Δ = 5184
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5184}=72$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-72)-72}{2*18}=\frac{0}{36}
=0
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-72)+72}{2*18}=\frac{144}{36}
=4
$