Recursive formula for arithmetic sequence

Which of the following answers is 7/9 simplified? 7/9 2/9 11/9 2/7

According to modern science, earth is about 4.5 billion years old and written human history extends back about 10,000 years. suppose the entire history of earth is represented with a 10-meter-long timeline, with the birth of earth on one end and today at the other end.

Identify the polynomial. a2b - cd3 a.monomial b.binomial c.trinomial d.four-term polynomial e.five-term polynomial