Question

i) Explain why 7×11×13+13 and 7×6×5×4×3×2×1+5 are composite numbers
ii) how will you show that (17×11×2)+(17×11×5) is composite number ​

Answer 1

Step-by-step explanation:

1)Given,

7×11×13+13 and 7×6×5×4×3×2×1+5

• 7×11×13+13
• 13(7×11+1)
• 13(77+1)
• 13(78)
• 1014=13×13×6(composite number)

7×6×5×4×3×2×1+5

• 5(7×6×4×3×2×1+1)
• 5(1008+1)
• 5(1009)

therefore,1009 can't be factorised number.

5 and 1009 as it factors .hence,it is a composite number.

2)given that,

(17×11×2)+(17×11×5)

17×11 common in both terms.

• so,17×11(2+5)
• 17×11(7)
• 17×11×7
• therefore 17×11×7 have 3 more factors than 1.
• so,it is a composite number.