Question

An arithmetic sequence is shown below.5, 1, -3, -7, . . .Which explicit formula can be used to determine the nth term of the sequence?A. an = 4n + 9B. an = -4n + 5C. an = -5n + 9D. an = -5n + 1

Answer 1

letter B

I'v just substitute 1, 2, 3, etc in each equation

Ex. when n = 2 a2 = -4(2) + 5

a2 = -8 + 5

a2 = -3

or when n = 3

a3 = -4(3) + 5

a3 = -12 + 5

a3 = -7

Doing this we obtain the values of the sequence 5, 1, -3, -7