4(x+3)(x+9)=0

Solution for 4(x+3)(x+9)=0 equation:

4(x+3)(x+9)=0

We multiply parentheses ..

4(+x^2+9x+3x+27)=0

We multiply parentheses

4x^2+36x+12x+108=0

We add all the numbers together, and all the variables

4x^2+48x+108=0

a = 4; b = 48; c = +108;
Δ = b2-4ac
Δ = 482-4·4·108
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{-(48)-24}{2*4}=\frac{-72}{8}
=-9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(48)+24}{2*4}=\frac{-24}{8}
=-3
$