math
posted by Babueddie on .
In an AP, the thirteenth term is 27, and the seventh term is three times the second term. Find the first term,?

a+12d = 27 , (#1)
a+6d = 3(a+d)
a+6d = 3a + 3d
3d = 2a
then 12d = 8a
in a+12d = 27
a + 8a = 27
9a = 27
a = 3
first term is 3