-4w(w-13)=-20

Solution for -4w(w-13)=-20 equation:

-4w(w-13)=-20

We move all terms to the left:

-4w(w-13)-(-20)=0

We add all the numbers together, and all the variables

-4w(w-13)+20=0

We multiply parentheses

-4w^2+52w+20=0

a = -4; b = 52; c = +20;
Δ = b2-4ac
Δ = 522-4·(-4)·20
Δ = 3024
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{3024}=\sqrt{144*21}=\sqrt{144}*\sqrt{21}=12\sqrt{21}$
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(52)-12\sqrt{21}}{2*-4}=\frac{-52-12\sqrt{21}}{-8}
$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(52)+12\sqrt{21}}{2*-4}=\frac{-52+12\sqrt{21}}{-8}
$