1.5a-0.2a(5a-6)=0

Solution for 1.5a-0.2a(5a-6)=0 equation:

1.5a-0.2a(5a-6)=0

We multiply parentheses

-0a^2+1.5a-0a=0

We add all the numbers together, and all the variables

-1a^2+0.5a=0

a = -1; b = 0.5; c = 0;
Δ = b2-4ac
Δ = 0.52-4·(-1)·0
Δ = 0.25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0.5)-\sqrt{0.25}}{2*-1}=\frac{-0.5-\sqrt{0.25}}{-2}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.5)+\sqrt{0.25}}{2*-1}=\frac{-0.5+\sqrt{0.25}}{-2}
$