18x(-3x+9)=0

Solution for 18x(-3x+9)=0 equation:

18x(-3x+9)=0

We multiply parentheses

-54x^2+162x=0

a = -54; b = 162; c = 0;
Δ = b2-4ac
Δ = 1622-4·(-54)·0
Δ = 26244
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{26244}=162$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(162)-162}{2*-54}=\frac{-324}{-108}
=+3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(162)+162}{2*-54}=\frac{0}{-108}
=0
$