424=(x+9)*x

Solution for 424=(x+9)*x equation:

424=(x+9)*x

We move all terms to the left:

424-((x+9)*x)=0


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

(x+9)*x

We multiply parentheses

x^2+9x

Back to the equation:

-(x^2+9x)


We get rid of parentheses

-x^2-9x+424=0

We add all the numbers together, and all the variables

-1x^2-9x+424=0

a = -1; b = -9; c = +424;
Δ = b2-4ac
Δ = -92-4·(-1)·424
Δ = 1777
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{-(-9)-\sqrt{1777}}{2*-1}=\frac{9-\sqrt{1777}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+\sqrt{1777}}{2*-1}=\frac{9+\sqrt{1777}}{-2}
$