Question

explain why 17X15X11X3X2+2X1 is a composite number

Answer 1

Definition of Composite number says :

$\bf The \: number \: having \: more \: than \: two \\ \bf multiples \: i.e. \: itself \: and \: 1, \: are \: called \\ \bf composite \: numbers.$

So, the given number should not have any number in common if it is prime number.

Let's see,

17 × 15 × 11 × 3 × 2 + 2 × 1

2 (17 × 15 × 11 × 3 × 1 + 1 × 1)

Since the number have 2 in common, we can say that the number's a composite number and not a prime number.

Hope it helps! ;)