2x(x+15)=15

Solution for 2x(x+15)=15 equation:

2x(x+15)=15

We move all terms to the left:

2x(x+15)-(15)=0

We multiply parentheses

2x^2+30x-15=0

a = 2; b = 30; c = -15;
Δ = b2-4ac
Δ = 302-4·2·(-15)
Δ = 1020
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:

$\sqrt{\Delta}=\sqrt{1020}=\sqrt{4*255}=\sqrt{4}*\sqrt{255}=2\sqrt{255}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-2\sqrt{255}}{2*2}=\frac{-30-2\sqrt{255}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+2\sqrt{255}}{2*2}=\frac{-30+2\sqrt{255}}{4}
$