1408=(30+2x)(18+2x)

Solution for 1408=(30+2x)(18+2x) equation:

1408=(30+2x)(18+2x)

We move all terms to the left:

1408-((30+2x)(18+2x))=0

We add all the numbers together, and all the variables

-((2x+30)(2x+18))+1408=0

We multiply parentheses ..

-((+4x^2+36x+60x+540))+1408=0


We calculate terms in parentheses: -((+4x^2+36x+60x+540)), so:

(+4x^2+36x+60x+540)

We get rid of parentheses

4x^2+36x+60x+540

We add all the numbers together, and all the variables

4x^2+96x+540

Back to the equation:

-(4x^2+96x+540)


We get rid of parentheses

-4x^2-96x-540+1408=0

We add all the numbers together, and all the variables

-4x^2-96x+868=0

a = -4; b = -96; c = +868;
Δ = b2-4ac
Δ = -962-4·(-4)·868
Δ = 23104
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{23104}=152$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-96)-152}{2*-4}=\frac{-56}{-8}
=+7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-96)+152}{2*-4}=\frac{248}{-8}
=-31
$