In an AP, where the first term is 7 and the common difference is 4,
first term a = 7 and common difference d = 4
Given, an = 5a
5a=5×75=35
Now, nth term of the AP, an=a+(n−1)d
an=7+(n−1)4
35=7+(n−1)4
n−1=7
n=8
∴ 8th term of the AP is five times the first term.