IXL | Write variable expressions for arithmetic sequences

Write an expression to describe the sequence below. Use n to represent the position of a term in the sequence, where n = 1 for the first term.

7, 8, 9, 10, ...

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question

Write an expression to describe the sequence below. Use n to represent the position of a term in the sequence, where n = 1 for the first term.

89, 90, 91, 92, ...

solution

The sequence 89, 90, 91, 92, ... looks like 1, 2, 3, 4, ... except each term is 88 larger. So, the expression that describes the sequence is n + 88. Check the first four terms:

To find the 1^st term, plug in n = 1.

n + 88 = 1 + 88 = 89

To find the 2^nd term, plug in n = 2.

n + 88 = 2 + 88 = 90

To find the 3^rd term, plug in n = 3.

n + 88 = 3 + 88 = 91

To find the 4^th term, plug in n = 4.

n + 88 = 4 + 88 = 92

The sequence 89, 90, 91, 92, ... is described by the expression n + 88.

Looking for more? Try these:

Lesson: Arithmetic sequences

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Not feeling ready yet? These can help:

FF.6Evaluate variable expressions for sequences

CC.8Write a linear function from a table

Lesson: Arithmetic sequences

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