Answer :
Answer:
2n+7
Step-by-step explanation:
Use this formaula whenever dealing with sequences where the difference between the numbers is constant.
a(n-1)+b
where a is the difference between the numbers
and
b is the first term, in this case, 9
So
2(n-1)+9
= 2n-2+9
= 2n+7
Now to check your answer, substitute a value of n into the equation, for example 3, and calculate.
2(3-1)+9= 13
If you look at the sequence, you'll see that the 3rd term is 13, so the expression is correct.
Hope this helps!