# List elements of the set in roster notation

• May 29th 2012, 08:23 PM
Lexy
List elements of the set in roster notation
{x | 2-x = 4 and x is a fraction}

The answer is -2, right? I'm only asking because the question before it asks the same thing and stipulates that x must be an integer. I have a feeling there is a trick somewhere.
• May 29th 2012, 08:36 PM
Prove It
Re: List elements of the set in roster notation
Quote:

Originally Posted by Lexy
{x | 2-x = 4 and x is a fraction}

The answer is -2, right? I'm only asking because the question before it asks the same thing and stipulates that x must be an integer. I have a feeling there is a trick somewhere.

The integers are a subset of the rationals (fractions), so yes, the answer is x = -2.
• May 30th 2012, 03:16 AM
emakarov
Re: List elements of the set in roster notation
If we assume that "fraction" here is a synonym of a "rational number," then the answer is {-2}, i.e., a set. However, it seems that "fraction" here means "a rational number that is not an integer." In this case, the answer is the empty set.