0=12x^2-16x-28

Solution for 0=12x^2-16x-28 equation:

0=12x^2-16x-28

We move all terms to the left:

0-(12x^2-16x-28)=0

We add all the numbers together, and all the variables

-(12x^2-16x-28)=0

We get rid of parentheses

-12x^2+16x+28=0

a = -12; b = 16; c = +28;
Δ = b2-4ac
Δ = 162-4·(-12)·28
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(16)-40}{2*-12}=\frac{-56}{-24}
=2+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16)+40}{2*-12}=\frac{24}{-24}
=-1
$