Arithmetic sequence problem

Question

An arithmetic sequence has a common difference of 3, and the fifth term of the sequence is seven times the first term of the sequence. List the first seven terms of this sequence.

Answer 1

d=3,

a5=7a1

a1+4d=7a1

4d=3a1

a1=4

a2=a1+d=7

a3=10

a4=13

a5=16

{4,7,10,13,16,..,}