50=x^2-2x

Solution for 50=x^2-2x equation:

50=x^2-2x

We move all terms to the left:

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

We get rid of parentheses

-x^2+2x+50=0

We add all the numbers together, and all the variables

-1x^2+2x+50=0

a = -1; b = 2; c = +50;
Δ = b2-4ac
Δ = 22-4·(-1)·50
Δ = 204
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:

$\sqrt{\Delta}=\sqrt{204}=\sqrt{4*51}=\sqrt{4}*\sqrt{51}=2\sqrt{51}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-2\sqrt{51}}{2*-1}=\frac{-2-2\sqrt{51}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+2\sqrt{51}}{2*-1}=\frac{-2+2\sqrt{51}}{-2}
$