6x(3x+9)=-36

Solution for 6x(3x+9)=-36 equation:

6x(3x+9)=-36

We move all terms to the left:

6x(3x+9)-(-36)=0

We add all the numbers together, and all the variables

6x(3x+9)+36=0

We multiply parentheses

18x^2+54x+36=0

a = 18; b = 54; c = +36;
Δ = b2-4ac
Δ = 542-4·18·36
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{-(54)-18}{2*18}=\frac{-72}{36}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(54)+18}{2*18}=\frac{-36}{36}
=-1
$