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the 4th term of AP is equal to 3 times the first term and 7th term excess which the third term by 1. find its nth term |
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Answer» Answer: a4=3×a1 =a+3d=3a 3d=2a-------1 EQ. a7-a3=1 a+6d-a+2d=1 a+8d=1 --------2 eq. from 1 d=2a/3 put in 2 a+8×2a/3=1 a+16a/3=1 3a+16a=3 19a=3 a=3/19----3 eq put in 1 d=2×3/19/3 d=38 a9=3/19×8×38 |
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