Question

How will you show that $(17\ast 11\ast 2)+(17\ast 11\ast 5)$ is a composite number? Explain.

Answer 1

The numbers are prime numbers and composite numbers.
Prime numbers can be divided by $1$ and itself.
A composite number has factors other than $1$ and itself.
$(17\ast 11\ast 2)+(17\ast 11\ast 5)$
$(17\ast 11)(2+5)=17\ast 11\ast 7$
The given expression has $7,11$ and $17$ as its factors.
$\therefore$ It is a composite number.