Question

use the lists of factors to answer the question.
factors of 9: 1, 3, 9
factors of 15: 1, 3, 5, 15
factors of 21: 1, 3, 7, 21
factors of 40: 1, 2, 4, 5, 8, 10, 20, 40

which pairs of numbers are relatively prime? check all that apply.
9 and 15
9 and 40
9 and 21
15 and 21
21 and 40

Explanation:

Define relatively prime numbers

Relatively prime numbers share only \(1\) as a common factor.

Analyze 9 and 15

Using the Factors and Greatest Common Factor knowledge points

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Analyze 9 and 40

Using the Factors and Greatest Common Factor knowledge points

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Analyze 9 and 21, and 15 and 21

Using the Factors and Greatest Common Factor knowledge points

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Analyze 21 and 40

Using the Factors and Greatest Common Factor knowledge points

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Answer:

• 9 and 15
• 9 and 40 (Correct answer)
• 9 and 21
• 15 and 21
• 21 and 40 (Correct answer)