340=2x*x

Solution for 340=2x*x equation:

340=2x*x

We move all terms to the left:

340-(2x*x)=0

We add all the numbers together, and all the variables

-(+2x*x)+340=0

We get rid of parentheses

-2x*x+340=0

Wy multiply elements

-2x^2+340=0

a = -2; b = 0; c = +340;
Δ = b2-4ac
Δ = 02-4·(-2)·340
Δ = 2720
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:

$\sqrt{\Delta}=\sqrt{2720}=\sqrt{16*170}=\sqrt{16}*\sqrt{170}=4\sqrt{170}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{170}}{2*-2}=\frac{0-4\sqrt{170}}{-4}
=-\frac{4\sqrt{170}}{-4}
=-\frac{\sqrt{170}}{-1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{170}}{2*-2}=\frac{0+4\sqrt{170}}{-4}
=\frac{4\sqrt{170}}{-4}
=\frac{\sqrt{170}}{-1}
$