-21w-4=5w^2

Solution for -21w-4=5w^2 equation:

-21w-4=5w^2

We move all terms to the left:

-21w-4-(5w^2)=0

determiningTheFunctionDomain
-5w^2-21w-4=0

a = -5; b = -21; c = -4;
Δ = b2-4ac
Δ = -212-4·(-5)·(-4)
Δ = 361
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{361}=19$
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-21)-19}{2*-5}=\frac{2}{-10}
=-1/5
$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-21)+19}{2*-5}=\frac{40}{-10}
=-4
$