Question

the 9th term of an ap is 3 times the 5th term. find the relationship between the first and common difference

Answer 1

a9 = 3A5
a + 8d = 3 [a + 4d]
a + 8d = 3a + 12d
a - 3a = 12d - 8d
-2a = 4d
-a = 2d
-1:2