Question

Write an explicit formula for an, the nth term of the sequence 13, 20, 27, ....

Answer: an
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Answer 1

See below ~

Step-by-step explanation:

Finding the common difference :

• 20 - 13
• 7

Formula :

• aₙ = aₙ₋₁ + 7

Answer 2

`\large \boxed{\sf 7n + 6}`

Step-by-step explanation:

Sequence: 13, 20, 27,...

Find common difference: second term - first term = 20 - 13 = 7

As it is an explicit arithmetic term:

⇒ a + (n - 1)d (a is the first term, d is common difference)

⇒ 13 + (n -1)(7)

⇒ 7n - 7 + 13

⇒ 7n + 6