Can someone please help me thsi the only one i need

a) The explicit formula is

b) The 31st term of the sequence is 222

Step-by-step explanation:

a) The explicit formula for an arithmetic sequence is:

The recursive formula for the sequence is

From this formula we can find the common difference by comparing to the general recursive formula:

This means the common difference d=7.

We now substitute the first term and the common difference  into the explicit formula: to obtain:

Expand to get:

Simplify:

b) To find the 31st term of this sequence, we substitute n=31 in to the the explicit formula,  to obtain:

Multiply to get:

Add to get:

Therefore the 31st term of the sequence is 222