Question

Which of the following sets represent an arithmetic sequence?
A
{­−5, ­−2, 1, 4, 7,…}\{­-5,\ ­-2,\ 1,\ 4,\ 7,\ldots \}{­−5, ­−2, 1, 4, 7,…}
B
{2, 5, 9, 14, 20,…}\{2,\ 5,\ 9,\ 14,\ 20,\ldots \}{2, 5, 9, 14, 20,…}
C
{­−3, 0, 4, 9, 15,…}\{­-3,\ 0,\ 4,\ 9,\ 15,\ldots \}{­−3, 0, 4, 9, 15,…}
D
{1, 3, 6, 10, 15,…}\{1,\ 3,\ 6,\ 10,\ 15,\ldots \}{1, 3, 6, 10, 15,…}

Answer 1

A only.

Differences:
A: -2−(−5)=3, 1−(−2)=3, 4−1=3, 7−4=3 → constant difference 3.
B: 3,4,5,6 (not constant).
C: 3,4,5,6 (not constant).
D: 2,3,4,5 (not constant).