-6a(-5-2a)=0

Solution for -6a(-5-2a)=0 equation:

-6a(-5-2a)=0

We add all the numbers together, and all the variables

-6a(-2a-5)=0

We multiply parentheses

12a^2+30a=0

a = 12; b = 30; c = 0;
Δ = b2-4ac
Δ = 302-4·12·0
Δ = 900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{900}=30$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-30}{2*12}=\frac{-60}{24}
=-2+1/2
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+30}{2*12}=\frac{0}{24}
=0
$