-3w^2-20w+7=0

Solution for -3w^2-20w+7=0 equation:

-3w^2-20w+7=0

a = -3; b = -20; c = +7;
Δ = b2-4ac
Δ = -202-4·(-3)·7
Δ = 484
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{484}=22$
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-22}{2*-3}=\frac{-2}{-6}
=1/3
$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+22}{2*-3}=\frac{42}{-6}
=-7
$