Question

Fifth term of an arithmetic squence is 21 and it's ninth term is 37. (a) what is it's common difference? (b) What is it's first term?
Anyone available
from mah followers...
Gud nigh.
user off
(⌐■-■)​

Answer 1

Answer:

(a) Common Difference = 4, (b) First Term = 5

Step-by-step explanation:

let First Term = a

let Common Difference = d

Let Number of Term = n

(a).

Using [a + (n - 1)d],

$x_{5}$ = a + 4d

$x_{9}$ = a + 8d

a + 8d - a - 4d = 37 - 21

4d = 16

d = 4

(b).

Substituting (d = 4) into $x_{5}$,

a + 4(4) = 21

a + 16 = 21

a = 21 - 16

a = 5