Question

Which expression describes the rule of this sequence? 3, 6, 9, 12, 15, 18

Answer 1

or

Answer 2

3n, 3+3 (3xn) or 3 + n

Answer 3

as u can see this is an arithmetic progression cause every number is got by adding 3 to the previous number,so
d=a2-a1=6-3=3
u can find an(general formula) by using
an=a1+d(n-1)
a1=3
d=3
substitute and u'll get
an=3+(n-1)*3
an=3+3n-3
an=3n