a-4a(-5a-2)=a

Solution for a-4a(-5a-2)=a equation:

a-4a(-5a-2)=a

We move all terms to the left:

a-4a(-5a-2)-(a)=0

We add all the numbers together, and all the variables

-4a(-5a-2)=0

We multiply parentheses

20a^2+8a=0

a = 20; b = 8; c = 0;
Δ = b2-4ac
Δ = 82-4·20·0
Δ = 64
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{64}=8$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-8}{2*20}=\frac{-16}{40}
=-2/5
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+8}{2*20}=\frac{0}{40}
=0
$