126=x^2+11x

Solution for 126=x^2+11x equation:

126=x^2+11x

We move all terms to the left:

126-(x^2+11x)=0

We get rid of parentheses

-x^2-11x+126=0

We add all the numbers together, and all the variables

-1x^2-11x+126=0

a = -1; b = -11; c = +126;
Δ = b2-4ac
Δ = -112-4·(-1)·126
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-11)-25}{2*-1}=\frac{-14}{-2}
=+7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-11)+25}{2*-1}=\frac{36}{-2}
=-18
$