0=60x^2+120x-40

Solution for 0=60x^2+120x-40 equation:

0=60x^2+120x-40

We move all terms to the left:

0-(60x^2+120x-40)=0

We add all the numbers together, and all the variables

-(60x^2+120x-40)=0

We get rid of parentheses

-60x^2-120x+40=0

a = -60; b = -120; c = +40;
Δ = b2-4ac
Δ = -1202-4·(-60)·40
Δ = 24000
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:

$\sqrt{\Delta}=\sqrt{24000}=\sqrt{1600*15}=\sqrt{1600}*\sqrt{15}=40\sqrt{15}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-120)-40\sqrt{15}}{2*-60}=\frac{120-40\sqrt{15}}{-120}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-120)+40\sqrt{15}}{2*-60}=\frac{120+40\sqrt{15}}{-120}
$