Question

show that the number 11×13×15 ×17 + 17 is a composite number

Answer 1

11×13 = 143
143×15 = 2145
2145×17 = 36465
36465 +17 =36482
last no. is 2 so it is divisible by 2 there fore has more than 1 divisor other than 1 and itself so it is composite.
Hope it helps u

Answer 2

11 × 13 × 15 × 17 + 17

= 17 ( 10 × 13 × 15 × 17 + 1)

.

Since we can take out 17 as a common factor, the number is a composite number.