Math, asked by dasgupta21, 9 months ago

Ans please someon
Mathematics​

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Answered by byaswanth2005
0

Answer:

i know the answer for the first one ok? just to help

Step-by-step explanation:

5th term =a+4d                                 formula(nth term of AP=a+(n-1)d)

9th term=a+8d

sum=a+4d+a+8d=30

2a+12d=30

2(a+6d)=30

a+6d=15------------------(1)

now solving the second part:

25th term =3 times 8th term

a+24d=3(a+7d)

a+24d=3a+21d

3d=2a

d=2a/3---------------------(2)

substituting value of d in 1 we get,

a+6(2a/3)=15

a+4a=15

5a=15

a=3

by substituting a in 2 we get,

d=6/3

d=2

so the AP is 3,5,7,9.....

mark as brainliest if you are satisfied with my answer

Answered by Mysterioushine
6

SOLUTION :

1) \: 5th \: term \: of \: an \: ap = a + 4d \\  \\ 9th \: term \: of \: an \: ap \:  = a + 8d \\  \\ given \: sum \: of \: the \: terms \:  = 30 \\  \\  =  >2a  \: +  12d = 30  - eq(1)\\  \\ 8th \: term \: of \: an \: ap \:  = a + 7d \\  \\  25th \: term \: of \: an \: ap = a + 24d \\  \\ relation \: between \: 8th \: and \: 25th \: term \: is \\  \\  \: a + 24d = 3(a + 7d) \\  \\  =  > a + 24d = 3a + 21d \\  \\  =  > 3d = 2a \:  \\  \\  =  > 2a - 3d = 0 - eq(2) \\  \\ subtracting \: eq(1) \: and \: eq(2) \\  \\  =  > 2a + 12d = 30 \\   \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  2a - 3d = 0 \\  \:  \:  \:  \:  \:  \:  \: ( - ) \:  \:  \: \:  \:  ( + ) \\  -  -  -  -  -  -  -  -  -  \\  \\  =  > 12d + 3d = 30 - 0 \\  \\  =  > 15d = 30 \\  \\  =  > d = 2 \\  \\ from \: eq(1) \: \\ \\  2a + 12(2) = 30 \\  \\  =  > 2a = 6 \\  \\  =  > a = 3 \\  \\ first \: term(a) = 3 \\  \\ 2nd \: term \:  = (a + d) = 3 + 2 = 5 \\  \\ 3rd \: term = (a + 2d) = 7 \\  \\ 4th \: term \:  = (a + 3d) = 9 \\  \\ 5th \: term \:  = (a + 4d) = 11

∴THE SEQUENCE IS 3 ,5 , 7,

9 ,....

HOPE IT HELPS !!!!

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