-9x^2+156x+480=0

Solution for -9x^2+156x+480=0 equation:

-9x^2+156x+480=0

a = -9; b = 156; c = +480;
Δ = b2-4ac
Δ = 1562-4·(-9)·480
Δ = 41616
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{41616}=204$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(156)-204}{2*-9}=\frac{-360}{-18}
=+20
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(156)+204}{2*-9}=\frac{48}{-18}
=-2+2/3
$