2x(-3x-15)=-12x

Solution for 2x(-3x-15)=-12x equation:

2x(-3x-15)=-12x

We move all terms to the left:

2x(-3x-15)-(-12x)=0

We multiply parentheses

-6x^2-30x-(-12x)=0

We get rid of parentheses

-6x^2-30x+12x=0

We add all the numbers together, and all the variables

-6x^2-18x=0

a = -6; b = -18; c = 0;
Δ = b2-4ac
Δ = -182-4·(-6)·0
Δ = 324
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{324}=18$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-18}{2*-6}=\frac{0}{-12}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+18}{2*-6}=\frac{36}{-12}
=-3
$