2x(x+4)=115

Solution for 2x(x+4)=115 equation:

2x(x+4)=115

We move all terms to the left:

2x(x+4)-(115)=0

We multiply parentheses

2x^2+8x-115=0

a = 2; b = 8; c = -115;
Δ = b2-4ac
Δ = 82-4·2·(-115)
Δ = 984
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:

$\sqrt{\Delta}=\sqrt{984}=\sqrt{4*246}=\sqrt{4}*\sqrt{246}=2\sqrt{246}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-2\sqrt{246}}{2*2}=\frac{-8-2\sqrt{246}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+2\sqrt{246}}{2*2}=\frac{-8+2\sqrt{246}}{4}
$