(3x+6)(6x+4)=64

Solution for (3x+6)(6x+4)=64 equation:

(3x+6)(6x+4)=64

We move all terms to the left:

(3x+6)(6x+4)-(64)=0

We multiply parentheses ..

(+18x^2+12x+36x+24)-64=0

We get rid of parentheses

18x^2+12x+36x+24-64=0

We add all the numbers together, and all the variables

18x^2+48x-40=0

a = 18; b = 48; c = -40;
Δ = b2-4ac
Δ = 482-4·18·(-40)
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{-(48)-72}{2*18}=\frac{-120}{36}
=-3+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(48)+72}{2*18}=\frac{24}{36}
=2/3
$