(X-3)(x+9)+27=0

Solution for (X-3)(x+9)+27=0 equation:

(X-3)(X+9)+27=0

We multiply parentheses ..

(+X^2+9X-3X-27)+27=0

We get rid of parentheses

X^2+9X-3X-27+27=0

We add all the numbers together, and all the variables

X^2+6X=0

a = 1; b = 6; c = 0;
Δ = b2-4ac
Δ = 62-4·1·0
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

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