-3x^2+9x+264=0

Solution for -3x^2+9x+264=0 equation:

-3x^2+9x+264=0

a = -3; b = 9; c = +264;
Δ = b2-4ac
Δ = 92-4·(-3)·264
Δ = 3249
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3249}=57$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(9)-57}{2*-3}=\frac{-66}{-6}
=+11
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+57}{2*-3}=\frac{48}{-6}
=-8
$