Question

Which function describes the arithmetic sequence shown?

−4, 0, 4, 8, 12, 16, ...
A) ƒ(x) = 4x + 8
B) ƒ(x) = 4x − 8
C) ƒ(x) = −4x + 8
D) ƒ(x) = −4x − 8

Answer 1

ƒ(x) = 4x − 8

Explanation:

an = a1 + d(n − 1), where an = nth term in the sequence, a1 = first term in the sequence, n = term number, and d = common difference.

first term = −4, common difference = 4

ƒ(x) = −4 + 4(x − 1) → ƒ(x) = −4 + 4x − 4 → ƒ(x) = 4x − 8

Answer 2

Answer: B) f(x) = 4x - 8
substitute in each value of x
f(1) = 4(1) - 8 = -4
f(2) = 4(2) - 8 = 0
f(3) = 4(3) - 8 = 4
etc.