x^2+6x+9=729

Solution for x^2+6x+9=729 equation:

x^2+6x+9=729

We move all terms to the left:

x^2+6x+9-(729)=0

We add all the numbers together, and all the variables

x^2+6x-720=0

a = 1; b = 6; c = -720;
Δ = b2-4ac
Δ = 62-4·1·(-720)
Δ = 2916
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2916}=54$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-54}{2*1}=\frac{-60}{2}
=-30
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+54}{2*1}=\frac{48}{2}
=24
$