810=(x+18)(x+15)

Solution for 810=(x+18)(x+15) equation:

810=(x+18)(x+15)

We move all terms to the left:

810-((x+18)(x+15))=0

We multiply parentheses ..

-((+x^2+15x+18x+270))+810=0


We calculate terms in parentheses: -((+x^2+15x+18x+270)), so:

(+x^2+15x+18x+270)

We get rid of parentheses

x^2+15x+18x+270

We add all the numbers together, and all the variables

x^2+33x+270

Back to the equation:

-(x^2+33x+270)


We get rid of parentheses

-x^2-33x-270+810=0

We add all the numbers together, and all the variables

-1x^2-33x+540=0

a = -1; b = -33; c = +540;
Δ = b2-4ac
Δ = -332-4·(-1)·540
Δ = 3249
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3249}=57$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-33)-57}{2*-1}=\frac{-24}{-2}
=+12
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-33)+57}{2*-1}=\frac{90}{-2}
=-45
$