3(x+2)(5x+9)=0

Solution for 3(x+2)(5x+9)=0 equation:

3(x+2)(5x+9)=0

We multiply parentheses ..

3(+5x^2+9x+10x+18)=0

We multiply parentheses

15x^2+27x+30x+54=0

We add all the numbers together, and all the variables

15x^2+57x+54=0

a = 15; b = 57; c = +54;
Δ = b2-4ac
Δ = 572-4·15·54
Δ = 9
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{9}=3$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(57)-3}{2*15}=\frac{-60}{30}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(57)+3}{2*15}=\frac{-54}{30}
=-1+4/5
$