2a(a+3)=0

Solution for 2a(a+3)=0 equation:

2a(a+3)=0

We multiply parentheses

2a^2+6a=0

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

$\sqrt{\Delta}=\sqrt{36}=6$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-6}{2*2}=\frac{-12}{4}
=-3
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+6}{2*2}=\frac{0}{4}
=0
$