630=42+13x+x^2

Solution for 630=42+13x+x^2 equation:

630=42+13x+x^2

We move all terms to the left:

630-(42+13x+x^2)=0

We get rid of parentheses

-x^2-13x-42+630=0

We add all the numbers together, and all the variables

-1x^2-13x+588=0

a = -1; b = -13; c = +588;
Δ = b2-4ac
Δ = -132-4·(-1)·588
Δ = 2521
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-13)-\sqrt{2521}}{2*-1}=\frac{13-\sqrt{2521}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-13)+\sqrt{2521}}{2*-1}=\frac{13+\sqrt{2521}}{-2}
$