(30+2x)(16+2x)=912

Solution for (30+2x)(16+2x)=912 equation:

(30+2x)(16+2x)=912

We move all terms to the left:

(30+2x)(16+2x)-(912)=0

We add all the numbers together, and all the variables

(2x+30)(2x+16)-912=0

We multiply parentheses ..

(+4x^2+32x+60x+480)-912=0

We get rid of parentheses

4x^2+32x+60x+480-912=0

We add all the numbers together, and all the variables

4x^2+92x-432=0

a = 4; b = 92; c = -432;
Δ = b2-4ac
Δ = 922-4·4·(-432)
Δ = 15376
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{15376}=124$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(92)-124}{2*4}=\frac{-216}{8}
=-27
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(92)+124}{2*4}=\frac{32}{8}
=4
$