x(2x+2)=8

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

x(2x+2)=8

We move all terms to the left:

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

We multiply parentheses

2x^2+2x-8=0

a = 2; b = 2; c = -8;
Δ = b2-4ac
Δ = 22-4·2·(-8)
Δ = 68
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:

$\sqrt{\Delta}=\sqrt{68}=\sqrt{4*17}=\sqrt{4}*\sqrt{17}=2\sqrt{17}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-2\sqrt{17}}{2*2}=\frac{-2-2\sqrt{17}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+2\sqrt{17}}{2*2}=\frac{-2+2\sqrt{17}}{4}
$