630=x(x+9)

Solution for 630=x(x+9) equation:

630=x(x+9)

We move all terms to the left:

630-(x(x+9))=0


We calculate terms in parentheses: -(x(x+9)), so:

x(x+9)

We multiply parentheses

x^2+9x

Back to the equation:

-(x^2+9x)


We get rid of parentheses

-x^2-9x+630=0

We add all the numbers together, and all the variables

-1x^2-9x+630=0

a = -1; b = -9; c = +630;
Δ = b2-4ac
Δ = -92-4·(-1)·630
Δ = 2601
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2601}=51$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-51}{2*-1}=\frac{-42}{-2}
=+21
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+51}{2*-1}=\frac{60}{-2}
=-30
$