Question

Q. Explain why 17 × 11 × 2 + 17 × 11 × 5 a composite number is.
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Answer 1

SOLUTION:

Now, what is a composite number ?

A composite number is a number which has more than two factor(one and number itself).

Examples of composite numbers-

20, which has factor 2,10,5 more than 2

Now answer:

17 × 11 × 2 + 17 × 11 × 5

= (17 × 11 × 2) + (17 × 11 × 5)

[take 17 and 11 as common]

= ( 17 × 11) ( 2 + 5 )

= 17 × 11 × 7

[as 2+5 = 7]

now,

method 1

let,

17 × 11 × 7 = a

so, a as more than two factors (1 and itself) i.e 17, 11, 7

now

method 2

17 × 11 × 7 = 1309

So,

1309 has more than two factor

Hence,

7 × 11 × 2 + 17 × 11 × 5 a composite number is.

Proved

Answer 2

Step-by-step explanation:

⇒17 × 11 × 2 + 17 ×11 × 5

=17×11 (2 + 5)

= 17 × 11 × 7

∵ the above no. has 3 prime factors its a composite no.