d We are given the sequences shown below.
a. 4, 7, 10, 13, …c. 24, 19, 14, …b. 3, 8, 13, …d. 7, 9.5, 12, …
To find the explicit equation for this sequence, let's start by seeing how the sequence is changing from term to term.
d. 7,→+2.5 9.5,→+2.5 12, …
Each term is obtained by adding
2.5 to the previous one, with the first term being
t(1)=7. We see that
t(2) is obtained by adding
2.5 to
7 one time, and
t(3) is obtained by adding
2.5 to
7 two times. Therefore,
t(n) can be obtained by adding
2.5 to
7 n−1 times. This leads us to the explicit formula
t(n)=7+2.5(n−1).