w(w+5)=20

Solution for w(w+5)=20 equation:

w(w+5)=20

We move all terms to the left:

w(w+5)-(20)=0

We multiply parentheses

w^2+5w-20=0

a = 1; b = 5; c = -20;
Δ = b2-4ac
Δ = 52-4·1·(-20)
Δ = 105
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-\sqrt{105}}{2*1}=\frac{-5-\sqrt{105}}{2}
$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+\sqrt{105}}{2*1}=\frac{-5+\sqrt{105}}{2}
$