3.3x(x-8)-x=1.2

Solution for 3.3x(x-8)-x=1.2 equation:

3.3x(x-8)-x=1.2

We move all terms to the left:

3.3x(x-8)-x-(1.2)=0

We add all the numbers together, and all the variables

-1x+3.3x(x-8)-1.2=0

We multiply parentheses

3x^2-1x-24x-1.2=0

We add all the numbers together, and all the variables

3x^2-25x-1.2=0

a = 3; b = -25; c = -1.2;
Δ = b2-4ac
Δ = -252-4·3·(-1.2)
Δ = 639.4
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-25)-\sqrt{639.4}}{2*3}=\frac{25-\sqrt{639.4}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+\sqrt{639.4}}{2*3}=\frac{25+\sqrt{639.4}}{6}
$