Question

Find the 18^th term of the arithmetic sequence whose common difference is d=5 and whose first term is ^a1=4

Answer 1

The n-th term of an arithmetic sequence can be found using the formula a_n = a_1 + (n-1)d, where a_n represents the n-th term, a_1 represents the first term, d represents the common difference, and n represents the position of the term in the sequence.

In this case, the first term a_1 is 4 and the common difference d is 5. We are asked to find the 18th term, which corresponds to n = 18.

Plugging these values into the formula, we have:

a_18 = 4 + (18-1)(5)
= 4 + 17(5)
= 4 + 85
= 89

Therefore, the 18th term of the arithmetic sequence is 89.