Find the 18th term of the sequence 5, 8, 11, 14, 17…

Solution:

The series 5, 8, 11, 14, 17… is an arithmetic progression with the first term a = 5 and the common difference d = 3

The nth term of the equation is therefore given:

T_n = a + (n - 1)d

Therefore the eighteenth term T₁₈ = 5 + (18 - 1)(3)

= 5 + (17)(3)

= 5 + 51

= 56

Let us take another series 77, 74, 71, 68….. and find the 18th term of the given series

a = 77 and d = -3

T₁₈ = 77 + (18 - 1)(-3)

= 77 + 17(-3)

= 77 - 51

= 26

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Find the 18th term of the sequence 5, 8, 11, 14, 17…

Summary:

The 18th term of the sequence 5, 8, 11, 14, 17… is 56