-480x^2-720x=84

Solution for -480x^2-720x=84 equation:

-480x^2-720x=84

We move all terms to the left:

-480x^2-720x-(84)=0

a = -480; b = -720; c = -84;
Δ = b2-4ac
Δ = -7202-4·(-480)·(-84)
Δ = 357120
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:

$\sqrt{\Delta}=\sqrt{357120}=\sqrt{2304*155}=\sqrt{2304}*\sqrt{155}=48\sqrt{155}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-720)-48\sqrt{155}}{2*-480}=\frac{720-48\sqrt{155}}{-960}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-720)+48\sqrt{155}}{2*-480}=\frac{720+48\sqrt{155}}{-960}
$