(4/5)s=20

Solution for (4/5)s=20 equation:

(4/5)s=20

We move all terms to the left:

(4/5)s-(20)=0


Domain of the equation: 5)s!=0

s!=0/1

s!=0

s∈R


We add all the numbers together, and all the variables

(+4/5)s-20=0

We multiply parentheses

4s^2-20=0

a = 4; b = 0; c = -20;
Δ = b2-4ac
Δ = 02-4·4·(-20)
Δ = 320
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{320}=\sqrt{64*5}=\sqrt{64}*\sqrt{5}=8\sqrt{5}$
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-8\sqrt{5}}{2*4}=\frac{0-8\sqrt{5}}{8}
=-\frac{8\sqrt{5}}{8}
=-\sqrt{5}
$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+8\sqrt{5}}{2*4}=\frac{0+8\sqrt{5}}{8}
=\frac{8\sqrt{5}}{8}
=\sqrt{5}
$