2x(x+10)=60

Solution for 2x(x+10)=60 equation:

2x(x+10)=60

We move all terms to the left:

2x(x+10)-(60)=0

We multiply parentheses

2x^2+20x-60=0

a = 2; b = 20; c = -60;
Δ = b2-4ac
Δ = 202-4·2·(-60)
Δ = 880
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:

$\sqrt{\Delta}=\sqrt{880}=\sqrt{16*55}=\sqrt{16}*\sqrt{55}=4\sqrt{55}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-4\sqrt{55}}{2*2}=\frac{-20-4\sqrt{55}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+4\sqrt{55}}{2*2}=\frac{-20+4\sqrt{55}}{4}
$