The third term of an ap is 3 and elements term is-21. Find its first term and common difference.
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3rd term = 3
11th term = -21
Let first term is a and common difference is d
then, 3rd term = a + 2d = 3
11th term = a + 10d = -21
(a + 10d) - (a + 2d) = -21 - 3
8d = -24 => d = -3 and a = 9
hence, first term = 9
common difference = -3
11th term = -21
Let first term is a and common difference is d
then, 3rd term = a + 2d = 3
11th term = a + 10d = -21
(a + 10d) - (a + 2d) = -21 - 3
8d = -24 => d = -3 and a = 9
hence, first term = 9
common difference = -3
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