Question

Give reason why each of the following is a composite number a) 7×11×17+17 b)5×6×7×8×9+7
C)5×7×19+19 d)13×17×19+13

Answer 1

composite no. is a no. which can be divided by more than 1 no.
like ATQ: a).7×11×17+17=17(7×11+1) where in this you have more than one product i.e 17 and (7×11+1)
like that other three were also following the same criteria. Therefore all are composite number.

hope...you will get understand.. thankyou