Write an explicit formula for the sequence . Use this to find the 80th term of the sequence that begins -3 , 1 , 5 , 9

Mathematics · Middle School · Mon Jan 18 2021

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Given : 

-3 , 1 , 5 , 9
Here 

a = -3

d = a2 - a1

= 1 -(-3)

= 1 + 3

= 4

n = 80

Formula : 

an = a + (n-1)d

a80 = -3 + (80-1)4

= -3 + 79 × 4

= -3 + 316

= 313

 

Hence, 80th term of the sequence is 313.