124=x2+2x

Solution for 124=x2+2x equation:

124=x2+2x

We move all terms to the left:

124-(x2+2x)=0

We add all the numbers together, and all the variables

-(+x^2+2x)+124=0

We get rid of parentheses

-x^2-2x+124=0

We add all the numbers together, and all the variables

-1x^2-2x+124=0

a = -1; b = -2; c = +124;
Δ = b2-4ac
Δ = -22-4·(-1)·124
Δ = 500
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:

$\sqrt{\Delta}=\sqrt{500}=\sqrt{100*5}=\sqrt{100}*\sqrt{5}=10\sqrt{5}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-10\sqrt{5}}{2*-1}=\frac{2-10\sqrt{5}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+10\sqrt{5}}{2*-1}=\frac{2+10\sqrt{5}}{-2}
$