Which of the following represents an explicit formula for the sequence:

8.2, 10, 11.8, 13.6

Tn = 6.4 + 1.8n

Step-by-step explanation:

Given

Sequence: 8.2, 10, 11.8, 13.6

Required

The formula of the sequence.

First, the type of the sequence needs to be determined (arithmetic or geometric)

It is an arithmetic sequence because each successive sequence is separated by a common difference ...

The common difference is represented by d and it's calculated as follows.

d = 10 - 8.2 or 11.8 - 10 or 13.6 - 11.8

Each of the above gives

d = 1.8

Now, that we have the common difference; the next is to determine the formula using the Arithmetic Progression formula.

Tn = T1 + (n - 1) d

Where T1 is the first term of the progression; T1 = 8.2

By substituting 8.2 for T1 and 1.8 for d.

This gives

Tn = 8.2 + (n - 1) * 1.8

Open bracket

Tn = 8.2 + 1.8 * n - 1 * 1.8

Tn = 8.2 + 1.8n - 1.8

Collect like terms

Tn = 8.2 - 1.8 + 1.8n

Tn = 6.4 + 1.8n

Hence, the formula of the sequence is Tn = 6.4 + 1.8n