(x-4)(x-4)=12

Solution for (x-4)(x-4)=12 equation:

(x-4)(x-4)=12

We move all terms to the left:

(x-4)(x-4)-(12)=0

We multiply parentheses ..

(+x^2-4x-4x+16)-12=0

We get rid of parentheses

x^2-4x-4x+16-12=0

We add all the numbers together, and all the variables

x^2-8x+4=0

a = 1; b = -8; c = +4;
Δ = b2-4ac
Δ = -82-4·1·4
Δ = 48
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{48}=\sqrt{16*3}=\sqrt{16}*\sqrt{3}=4\sqrt{3}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-4\sqrt{3}}{2*1}=\frac{8-4\sqrt{3}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+4\sqrt{3}}{2*1}=\frac{8+4\sqrt{3}}{2}
$