Multiple of 3

If (x/2-x/6) is an  integer, show why x must be a multiple of 3.
Source: NCTM Mathematics Teacher, October 2006

Solution
x/2-x/6=x/3 which is a rational number. Clearly, for x/2-x/6 to be an integer x must be a multiple of 3.

Answer: Shown in solution

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About mvtrinh

Retired high school math teacher.
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