I need help with solving an equation.

Is the equation

0   =  I^(1/r) - I^(2/r) +  d     ????

Or is it

0  =  I^1  / r  +  I^(2) / r  + d      ????

Oh...OK....I understand now

We have that

0  =  I₁ / r  + I₂ / r  + d     subtract   d from both sides

-d  =   I₁ / r  + I₂ / r       note that the right side can be written as

-d =   [  I₁ + I₂ ]  / r      multiply both sides by r

-rd  =   I₁ + I₂         divide both sides by -d

r =     [  I₁ + I₂ ]  /  -d 

r  =   - [ I₁ + I₂ ] / d  

P.S.  ......if the "d"  is supposed to be a part of the second denominator, we have

0  =  I₁ / r  + I₂ /  (r  + d)      get a common denominator

0 =   [ I₁ ( r + d)  +  I₂ r ]  /  [ r (r + d) ]      multiply boh sides by   [ r (r + d) ]

0 *  [ r (r + d) ]  =   [ I₁ ( r + d)  +  I₂ r ] 

0  =   [ I₁ ( r + d)  +  I₂ r ]    simplify

0  =  I₁ r + I₁d +   I₂ r       subtract  I₁d  from both sides

- I₁d     =    I₁ r  +   I₂ r      factor the right side

- I₁d   =   r  [ I₁ + I₂ ]         divide both sides by  [ I₁ + I₂ ] 

- I₁d  /   [ I₁ + I₂ ]    =   r

One last thing, Sekai

The  "1"    and  "2"   are known as "subscripts"

"Indexes"  usually refer to exponents