3x(x+10)+18=-9

Solution for 3x(x+10)+18=-9 equation:

3x(x+10)+18=-9

We move all terms to the left:

3x(x+10)+18-(-9)=0

We add all the numbers together, and all the variables

3x(x+10)+27=0

We multiply parentheses

3x^2+30x+27=0

a = 3; b = 30; c = +27;
Δ = b2-4ac
Δ = 302-4·3·27
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{576}=24$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-24}{2*3}=\frac{-54}{6}
=-9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+24}{2*3}=\frac{-6}{6}
=-1
$