528=(3x+12)(2x+10)

Solution for 528=(3x+12)(2x+10) equation:

528=(3x+12)(2x+10)

We move all terms to the left:

528-((3x+12)(2x+10))=0

We multiply parentheses ..

-((+6x^2+30x+24x+120))+528=0


We calculate terms in parentheses: -((+6x^2+30x+24x+120)), so:

(+6x^2+30x+24x+120)

We get rid of parentheses

6x^2+30x+24x+120

We add all the numbers together, and all the variables

6x^2+54x+120

Back to the equation:

-(6x^2+54x+120)


We get rid of parentheses

-6x^2-54x-120+528=0

We add all the numbers together, and all the variables

-6x^2-54x+408=0

a = -6; b = -54; c = +408;
Δ = b2-4ac
Δ = -542-4·(-6)·408
Δ = 12708
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:

$\sqrt{\Delta}=\sqrt{12708}=\sqrt{36*353}=\sqrt{36}*\sqrt{353}=6\sqrt{353}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-54)-6\sqrt{353}}{2*-6}=\frac{54-6\sqrt{353}}{-12}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-54)+6\sqrt{353}}{2*-6}=\frac{54+6\sqrt{353}}{-12}
$