72=2*22/7*r(2)

Solution for 72=2*22/7*r(2) equation:

72=2*22/7r(2)

We move all terms to the left:

72-(2*22/7r(2))=0


Domain of the equation: 7r2)!=0

r!=0/1

r!=0

r∈R


We add all the numbers together, and all the variables

-(+2*22/7r2)+72=0

We get rid of parentheses

-2*22/7r2+72=0

We multiply all the terms by the denominator


72*7r2-2*22=0

We add all the numbers together, and all the variables

72*7r2-44=0

Wy multiply elements

504r^2-44=0

a = 504; b = 0; c = -44;
Δ = b2-4ac
Δ = 02-4·504·(-44)
Δ = 88704
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{88704}=\sqrt{576*154}=\sqrt{576}*\sqrt{154}=24\sqrt{154}$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-24\sqrt{154}}{2*504}=\frac{0-24\sqrt{154}}{1008}
=-\frac{24\sqrt{154}}{1008}
=-\frac{\sqrt{154}}{42}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+24\sqrt{154}}{2*504}=\frac{0+24\sqrt{154}}{1008}
=\frac{24\sqrt{154}}{1008}
=\frac{\sqrt{154}}{42}
$