3(3x^2+1)=12x

Solution for 3(3x^2+1)=12x equation:

3(3x^2+1)=12x

We move all terms to the left:

3(3x^2+1)-(12x)=0

We add all the numbers together, and all the variables

-12x+3(3x^2+1)=0

We multiply parentheses

9x^2-12x+3=0

a = 9; b = -12; c = +3;
Δ = b2-4ac
Δ = -122-4·9·3
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-6}{2*9}=\frac{6}{18}
=1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+6}{2*9}=\frac{18}{18}
=1
$