-2x^2-6=-168

Solution for -2x^2-6=-168 equation:

-2x^2-6=-168

We move all terms to the left:

-2x^2-6-(-168)=0

We add all the numbers together, and all the variables

-2x^2+162=0

a = -2; b = 0; c = +162;
Δ = b2-4ac
Δ = 02-4·(-2)·162
Δ = 1296
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1296}=36$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-36}{2*-2}=\frac{-36}{-4}
=+9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+36}{2*-2}=\frac{36}{-4}
=-9
$