30=2x^2+12-50

Solution for 30=2x^2+12-50 equation:

30=2x^2+12-50

We move all terms to the left:

30-(2x^2+12-50)=0

We get rid of parentheses

-2x^2-12+50+30=0

We add all the numbers together, and all the variables

-2x^2+68=0

a = -2; b = 0; c = +68;
Δ = b2-4ac
Δ = 02-4·(-2)·68
Δ = 544
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:

$\sqrt{\Delta}=\sqrt{544}=\sqrt{16*34}=\sqrt{16}*\sqrt{34}=4\sqrt{34}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{34}}{2*-2}=\frac{0-4\sqrt{34}}{-4}
=-\frac{4\sqrt{34}}{-4}
=-\frac{\sqrt{34}}{-1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{34}}{2*-2}=\frac{0+4\sqrt{34}}{-4}
=\frac{4\sqrt{34}}{-4}
=\frac{\sqrt{34}}{-1}
$