-3y^2-30y+72=0

Solution for -3y^2-30y+72=0 equation:

-3y^2-30y+72=0

a = -3; b = -30; c = +72;
Δ = b2-4ac
Δ = -302-4·(-3)·72
Δ = 1764
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1764}=42$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-42}{2*-3}=\frac{-12}{-6}
=+2
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+42}{2*-3}=\frac{72}{-6}
=-12
$