26=2x^2-4x

Solution for 26=2x^2-4x equation:

26=2x^2-4x

We move all terms to the left:

26-(2x^2-4x)=0

We get rid of parentheses

-2x^2+4x+26=0

a = -2; b = 4; c = +26;
Δ = b2-4ac
Δ = 42-4·(-2)·26
Δ = 224
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:

$\sqrt{\Delta}=\sqrt{224}=\sqrt{16*14}=\sqrt{16}*\sqrt{14}=4\sqrt{14}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-4\sqrt{14}}{2*-2}=\frac{-4-4\sqrt{14}}{-4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+4\sqrt{14}}{2*-2}=\frac{-4+4\sqrt{14}}{-4}
$