2(x+3)(x+3)=18

Solution for 2(x+3)(x+3)=18 equation:

2(x+3)(x+3)=18

We move all terms to the left:

2(x+3)(x+3)-(18)=0

We multiply parentheses ..

2(+x^2+3x+3x+9)-18=0

We multiply parentheses

2x^2+6x+6x+18-18=0

We add all the numbers together, and all the variables

2x^2+12x=0

a = 2; b = 12; c = 0;
Δ = b2-4ac
Δ = 122-4·2·0
Δ = 144
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{144}=12$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-12}{2*2}=\frac{-24}{4}
=-6
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+12}{2*2}=\frac{0}{4}
=0
$