The "5" is in the denominator and a denominator is
always DIVIDED.

We want to get rid of the DIVIDED "5", so there will 
just be "n" left on the left side of the equation.

The opposite operation from DIVISION is MULTIPLICATION.

So if we MULTIPLY the left side by "5" it will cancel
out the DIVIDED "5", and just the "n" will be left.

However if we multiply the left side by "5", we must
also multiply the right side by 5.

So we start by writing this:

            

and we copy it over, putting a MULTIPLIED "5" before both sides:

          

Now we copy it over cancelling the 5's on the left, like this:

          

and then we copy that over multiplying the right side 5×17 = 85

and we write this last:

          

The whole thing should look like this:

              
           
          
              
 
Edwin