Question

Show that the sequence defined by an=5n-7 is an ap.find its common difference

Answer 1

an = 5n - 7

a1 = 5×1 -7 = -2
a2 = 5×2 - 7 = 3
a3 = 5×3 - 7 = 8

d = a2 - a1 = a3 - a2

d = 3-(-2) = 8 - 3

d = 5 = 5

Hence, d = 5


Thanks