I was given this question and don't really know where to start, any help would be much appreciated.. "If the sequence a is arithmetic, and a_3 = 5, and a_5 = 15, find a_9" Is the awnser 35?
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Originally Posted by 14041471 I was given this question and don't really know where to start, any help would be much appreciated.. "If the sequence a is arithmetic, and a_3 = 5, and a_5 = 15, find a_9" Is the awnser 35? Yes
Originally Posted by 14041471 "If the sequence a is arithmetic, and a_3 = 5, and a_5 = 15, find a_9" If the sequence is arithmetic, then the same amount "d" is added at each stage. Then a_4 = 5 + d and a_5 = a_4 + d = (5 + d) + d = 5 + 2d = 15. Then 2d = 10, so d = 5. Originally Posted by 14041471 Is the awnser 35? Yup!
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