Exit Quiz
Question 1 of 6
1
of 6
Which two sequences from the options below could be added to make the quadratic sequence which starts: 3, 7, 13, 21, ...?
Select 2 answers
$$n^2: 1, 4, 9, 16, ...$$
$$2n^2: 2, 8, 18, 32, ...$$
$$-2n+3 : 1, -1, -3, -5, ...$$
$$n+1 : 2, 3, 4, 5, ...$$
$$3n-2: 1, 4, 7, 10, ...$$
This sequence has a common second difference of 2 so will be of the form $$n^2 + bn + c$$. What sequence do you need to add to $$n^2 $$ to get 3, 7, 13, 21, ... ?
Need a hint?
Check