(8+2x)(10+2x)=1440

Solution for (8+2x)(10+2x)=1440 equation:

(8+2x)(10+2x)=1440

We move all terms to the left:

(8+2x)(10+2x)-(1440)=0

We add all the numbers together, and all the variables

(2x+8)(2x+10)-1440=0

We multiply parentheses ..

(+4x^2+20x+16x+80)-1440=0

We get rid of parentheses

4x^2+20x+16x+80-1440=0

We add all the numbers together, and all the variables

4x^2+36x-1360=0

a = 4; b = 36; c = -1360;
Δ = b2-4ac
Δ = 362-4·4·(-1360)
Δ = 23056
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:

$\sqrt{\Delta}=\sqrt{23056}=\sqrt{16*1441}=\sqrt{16}*\sqrt{1441}=4\sqrt{1441}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(36)-4\sqrt{1441}}{2*4}=\frac{-36-4\sqrt{1441}}{8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(36)+4\sqrt{1441}}{2*4}=\frac{-36+4\sqrt{1441}}{8}
$