Explain Why 3 × 5 × 7 + 7 Is a Composite Number

Video Explanation

Watch the video below to understand the complete explanation step by step:

Solution

Question: Explain why 3 × 5 × 7 + 7 is a composite number.

Step 1: Write the Given Expression

3 × 5 × 7 + 7

Step 2: Take 7 as Common Factor

3 × 5 × 7 + 7 = 7 (3 × 5 + 1)

= 7 (15 + 1)

= 7 × 16

Step 3: Draw the Conclusion

Since 7 × 16 is a product of two integers greater than 1, the given number has factors other than 1 and itself.

Final Answer

∴ 3 × 5 × 7 + 7 is a composite number.

Conclusion

Thus, by factorising the given expression, we conclude that the number is composite because it can be expressed as a product of integers greater than 1.