(2x+12)(2x+18)-(12*18)=99

Solution for (2x+12)(2x+18)-(12*18)=99 equation:

(2x+12)(2x+18)-(12*18)=99

We move all terms to the left:

(2x+12)(2x+18)-(12*18)-(99)=0

determiningTheFunctionDomain
(2x+12)(2x+18)-99-(12*18)=0

We add all the numbers together, and all the variables

(2x+12)(2x+18)-99-216=0

We add all the numbers together, and all the variables

(2x+12)(2x+18)-315=0

We multiply parentheses ..

(+4x^2+36x+24x+216)-315=0

We get rid of parentheses

4x^2+36x+24x+216-315=0

We add all the numbers together, and all the variables

4x^2+60x-99=0

a = 4; b = 60; c = -99;
Δ = b2-4ac
Δ = 602-4·4·(-99)
Δ = 5184
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5184}=72$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(60)-72}{2*4}=\frac{-132}{8}
=-16+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(60)+72}{2*4}=\frac{12}{8}
=1+1/2
$