2x^2-390=2

Solution for 2x^2-390=2 equation:

2x^2-390=2

We move all terms to the left:

2x^2-390-(2)=0

We add all the numbers together, and all the variables

2x^2-392=0

a = 2; b = 0; c = -392;
Δ = b2-4ac
Δ = 02-4·2·(-392)
Δ = 3136
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3136}=56$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-56}{2*2}=\frac{-56}{4}
=-14
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+56}{2*2}=\frac{56}{4}
=14
$