Apositive integer is twice another. the difference of the reciprocals of the two positive integers is 1/8. find the two integers.

To solve this problem you must apply the proccedure shown below:
 1. You have:
 x: the positive integer that is twice another.
 y: the other positive integer.
 2. Therefore, you must write a system of equations, as following:
 x=2y
 (1/y)-/(1/x)=1/8
 3. By susbtitution, you obtain:
 (1/y)-/(1/2y)=1/8
 y=4
 x=2x4
 x=8
 The answer is: 8 and 4.

Where is the table?