x(20-3x)=0

Solution for x(20-3x)=0 equation:

x(20-3x)=0

We add all the numbers together, and all the variables

x(-3x+20)=0

We multiply parentheses

-3x^2+20x=0

a = -3; b = 20; c = 0;
Δ = b2-4ac
Δ = 202-4·(-3)·0
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-20}{2*-3}=\frac{-40}{-6}
=6+2/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+20}{2*-3}=\frac{0}{-6}
=0
$