396=(13+2x)(17+2x)

Solution for 396=(13+2x)(17+2x) equation:

396=(13+2x)(17+2x)

We move all terms to the left:

396-((13+2x)(17+2x))=0

We add all the numbers together, and all the variables

-((2x+13)(2x+17))+396=0

We multiply parentheses ..

-((+4x^2+34x+26x+221))+396=0


We calculate terms in parentheses: -((+4x^2+34x+26x+221)), so:

(+4x^2+34x+26x+221)

We get rid of parentheses

4x^2+34x+26x+221

We add all the numbers together, and all the variables

4x^2+60x+221

Back to the equation:

-(4x^2+60x+221)


We get rid of parentheses

-4x^2-60x-221+396=0

We add all the numbers together, and all the variables

-4x^2-60x+175=0

a = -4; b = -60; c = +175;
Δ = b2-4ac
Δ = -602-4·(-4)·175
Δ = 6400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6400}=80$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-60)-80}{2*-4}=\frac{-20}{-8}
=2+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-60)+80}{2*-4}=\frac{140}{-8}
=-17+1/2
$