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

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

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

We multiply parentheses ..

(+5x^2+15x+3x+9)=0

We get rid of parentheses

5x^2+15x+3x+9=0

We add all the numbers together, and all the variables

5x^2+18x+9=0

a = 5; b = 18; c = +9;
Δ = b2-4ac
Δ = 182-4·5·9
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{-(18)-12}{2*5}=\frac{-30}{10}
=-3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+12}{2*5}=\frac{-6}{10}
=-3/5
$