Which of the following statements is FALSE?

1996

Which of the following statements is FALSE?

  1. A.

    The set of rational numbers is an abelian group under addition

  2. B.

    The set of integers is an abelian group under addition

  3. C.

    The set of rational numbers form an abelian group under multiplication

  4. D.

    The set of real numbers excluding zero is an abelian group under multiplication

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Show answer & explanation

Correct answer: C

The set of rational numbers form an abelian group under multiplication

Solution:

A group under multiplication must contain an identity element and every element must have an inverse within the set.

For rational numbers under multiplication, the element 0 has no multiplicative inverse because:

1/0

is undefined.

Hence, the set of all rational numbers is not a group under multiplication.

Therefore, statement (C) is false.

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