Question

1,4,7,------,find its 21 th term​

Answer 1

Answer:

61

Explanation:

use formula (a+(n-1)d)

a=1

n=21

d=3

Answer 2

an = a + (n - 1) d

where,

a = first term = 1

an = nth term = ?

n = total no. of terms = 21

d = difference = 3 (4 - 1 = 3)

a21 = 1 + (21 - 1) 3

= 1 + 60

a21 = 61