Math, asked by vaibhavaswal2, 1 year ago

If 7th times the 7th term of an A.P is equal to 11 times it's 11th term, then find its 18th term.

Answers

Answered by pmtibrahim18
15

7(a+6d) = 11(a+10d)

7a+42d = 11a+110d

- 4a = 68d

a = 68d/ -4 = -17 d         eq.1

so 18 th term is

a +17d

ie : putting a value from eq.1

- 17d +17d = 0

therefore the 18th term is 0


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Answered by Anonymous
17

given :-

7 ( a7 ) = 11 ( a11 )

7 ( a + 6d ) = 11 ( a + 10d )

7a + 42d = 11a + 110d

7a - 11a + 42d - 110d = 0

4a - 68d = 0

a - 17d = 0

a = 17d ... ( i )

To find 18th term

a18 = a + ( n - 1 )d

a18 = a + 17d

a18 = 17d + 17d

a18 = 34d

Answered by Anonymous
45

given :-

7 ( a7 ) = 11 ( a11 )

7 ( a + 6d ) = 11 ( a + 10d )

7a + 42d = 11a + 110d

7a - 11a + 42d - 110d = 0

4a - 68d = 0

a - 17d = 0

a = 17d ... ( i )

To find 18th term

a18 = a + ( n - 1 )d

a18 = a + 17d

a18 = 17d + 17d

a18 = 34d

Answered by Anonymous
24

given :-

7 ( a7 ) = 11 ( a11 )

7 ( a + 6d ) = 11 ( a + 10d )

7a + 42d = 11a + 110d

7a - 11a + 42d - 110d = 0

4a - 68d = 0

a - 17d = 0

a = 17d ... ( i )

To find 18th term

a18 = a + ( n - 1 )d

a18 = a + 17d

a18 = 17d + 17d

a18 = 34d

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