Expand the expression in the equation
$$- 4 \left(x - 3\right) \left(3 x - 11\right) + 4 = 0$$
We get the quadratic equation
$$- 12 x^{2} + 80 x - 128 = 0$$
This equation is of the form
a*x^2 + b*x + c = 0
A quadratic equation can be solved
using the discriminant.
The roots of the quadratic equation:
$$x_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$x_{2} = \frac{- \sqrt{D} - b}{2 a}$$
where D = b^2 - 4*a*c - it is the discriminant.
Because
$$a = -12$$
$$b = 80$$
$$c = -128$$
, then
D = b^2 - 4 * a * c =
(80)^2 - 4 * (-12) * (-128) = 256
Because D > 0, then the equation has two roots.
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
or
$$x_{1} = \frac{8}{3}$$
$$x_{2} = 4$$