write an expression for the nth term
in Other Math Topics by

Your answer

Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
To avoid this verification in future, please log in or register.

1 Answer

There is a common difference of 2. For the nth term a₁=7, a₂=9, a₃=11, a₄=13, a₅=15 where n goes from 1 to 5. Subtract 1 from each term: 6, 8, 10, 12, 14. Now halve each: 3, 4, 5, 6, 7, which is 1+2, 2+2, 3+2, 4+2, 5+2.

So, by reversing the operations, a[n] (meaning a sub n)=2(n+2)+1=2n+5. (The reverse of ½ is 2 and the reverse of subtract is add.) Check: if n=1 a₁=2×1+5=7; n=2, a₂=2×2+5=9.

Therefore a[n]=2n+5.

 

by Top Rated User (608k points)

Related questions

1 answer
1 answer
3 answers
1 answer
asked Mar 20, 2015 in Algebra 2 Answers by anonymous | 322 views
1 answer
Welcome to MathHomeworkAnswers.org, where students, teachers and math enthusiasts can ask and answer any math question. Get help and answers to any math problem including algebra, trigonometry, geometry, calculus, trigonometry, fractions, solving expression, simplifying expressions and more. Get answers to math questions. Help is always 100% free!
82,131 questions
86,608 answers
2,246 comments
75,816 users