Question

For the following arithmetic sequence, find the value of a and d and hence find the term indicated: - 2 , 2 , 6 , 10 , . . . , t 7. If the first term of an arithmetic sequence is 7 and the 4th term is 28, find the value of d.

Answer 1

Answer:

$t_{7}$ = 22   is the answer to the first question

d = 4 is the answer to the second question

Step-by-step explanation:

use the formula $a_{n} = a + (n - 1)d$

6 - 2 = 4 = d  a = -2  n = 7

$t_{7}$ = -2 + (7 - 1)4

   = -2 + 6(4)

   = -2 + 24

   = 22

use the formula $a_{n} = a + (n - 1)d$

a = 7

n = 4    

$a_{4} = 28$

28 = 7 + (7 - 1)d

     = 4 + 6d

24 = 6d

d = 4