-4x(x-6)-6=-30

Solution for -4x(x-6)-6=-30 equation:

-4x(x-6)-6=-30

We move all terms to the left:

-4x(x-6)-6-(-30)=0

We add all the numbers together, and all the variables

-4x(x-6)+24=0

We multiply parentheses

-4x^2+24x+24=0

a = -4; b = 24; c = +24;
Δ = b2-4ac
Δ = 242-4·(-4)·24
Δ = 960
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:

$\sqrt{\Delta}=\sqrt{960}=\sqrt{64*15}=\sqrt{64}*\sqrt{15}=8\sqrt{15}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(24)-8\sqrt{15}}{2*-4}=\frac{-24-8\sqrt{15}}{-8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(24)+8\sqrt{15}}{2*-4}=\frac{-24+8\sqrt{15}}{-8}
$