(18x+2x)(10+2x)=768

Solution for (18x+2x)(10+2x)=768 equation:

(18x+2x)(10+2x)=768

We move all terms to the left:

(18x+2x)(10+2x)-(768)=0

We add all the numbers together, and all the variables

(+20x)(2x+10)-768=0

We multiply parentheses ..

(+40x^2+200x)-768=0

We get rid of parentheses

40x^2+200x-768=0

a = 40; b = 200; c = -768;
Δ = b2-4ac
Δ = 2002-4·40·(-768)
Δ = 162880
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{162880}=\sqrt{64*2545}=\sqrt{64}*\sqrt{2545}=8\sqrt{2545}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(200)-8\sqrt{2545}}{2*40}=\frac{-200-8\sqrt{2545}}{80}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(200)+8\sqrt{2545}}{2*40}=\frac{-200+8\sqrt{2545}}{80}
$