the 5th term of an aritamatic sequence 38and the 9th term is 66 what is its first term and the 15th term
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Answered by
0
Answer:
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Step-by-step explanation:
5th term= a+4d
Or 38=a+4d -equation 1
9th term=a+8d
Or 66=a+8d -equation 2
Eq.1-eq2
Or a+4d=38
a+8d=66
- - -
Or -4d= -28
Or d=28/4
d=7
Putting value of d in equation 1
a+4d=38
Or a+28=38
Or a=38-28
Or a=10
Now 25th term
25th term = a+24d
Or 10+24*7
Or 25th term=10+168
Or 25th term=178
Answered by
0
The first term is 10 and the 15th term is 138
Step-by-step explanation:
5th term-38
9th term-66
15th term =?
An=a+(n-1)xd
38=a+(5-1)xd
38=a+4d -----(1)
An=a+(n-1)xd
66=a+(9-1)xd
66=a+8d-----(2)
solving both the equations:-
a+4d=38
a+8d=66
- - -
-4d=-28
4d=28
d = 28/4
d=7
put d in (1) to find a
a = 10
put a =10 and d= 7 in
An=a+(n-1)d
you will get the answer as 1st term =10
15th term = 138
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