Answer:
[tex]\sf \t_{43} = 381[/tex]381
Step-by-step explanation:
3,12,21 ..........
Find the common difference.
Common difference = second term - first term
d = 12 -3
[tex]\sf \boxed{\bf d = 9}[/tex]
[tex]\sf \boxed{\bf t_n = a + (n-1)*d}[/tex]
n = 43 ; d = 9 ; a = 3
[tex]\sf t_{43}=3 + (43-1)*9\\\\[/tex]
= 3 + 42*9
= 3 + 378
= 381
