x.3(6x-1)=12

Solution for x.3(6x-1)=12 equation:

x.3(6x-1)=12

We move all terms to the left:

x.3(6x-1)-(12)=0

We multiply parentheses

6x^2-1x-12=0

a = 6; b = -1; c = -12;
Δ = b2-4ac
Δ = -12-4·6·(-12)
Δ = 289
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{289}=17$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1)-17}{2*6}=\frac{-16}{12}
=-1+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+17}{2*6}=\frac{18}{12}
=1+1/2
$