Question

the 5th term of an as is 38 and 9th term is 66 what is its 25th term

Answer 1

↑ Here is your answer ↓
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$a_5 = 38$

$a+4d = 38 --(1)$

$a_9=66$

$a+8d = 66 --(2)$

Subtract (1) from (2)

$a+8d = 66 \\ a+4d=38 \\ ------ \\ 0 + 4d = 28$

$4d = 28$

$d = \dfrac{28}{4}$

$d = 7 --(3)$

Sub (3) in (1)

$a+4(7)=38$

$a+28=38$

$a=10$

Now, 25th term

$a_{25} = a+24d$

$a_{25} = 10 + 24(7)$

$a_{25} = 10+168$

$a_{25} = 178$

Answer 2

Answer:

Most easieat way

Step-by-step explanation:

a5= 38

a9=66

9-5=4

66-38=28

Common difference:28÷4=7

25th term=

To the 5th term

25-5=20times common difference

5th term=38+(20×7)=

38+140=148