3x(-10-2x)=0

Solution for 3x(-10-2x)=0 equation:

3x(-10-2x)=0

We add all the numbers together, and all the variables

3x(-2x-10)=0

We multiply parentheses

-6x^2-30x=0

a = -6; b = -30; c = 0;
Δ = b2-4ac
Δ = -302-4·(-6)·0
Δ = 900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{900}=30$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-30}{2*-6}=\frac{0}{-12}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+30}{2*-6}=\frac{60}{-12}
=-5
$