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Find 4 consecutive terms in an AP such that their sum is -40 and the sum of first and third term is -18 |
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Answer» ET three NUMBERS be a - d, a, a + d given a - d + a + a + d = 21 3a = 21 ∴a=7 (a + d) (a - d) a = 315 =(7+d)(7−d)×7=315 =(7 −d 2 )=45 =7 2 −45=d 2
=49−45=d 2
=4=d 2
d=±2 numbers are 7 - 2 , 7 , 7 + 2 = 5 , 7 , 9 Step-by-step explanation: A] Let three numbers be a - d, a, a + d given a - d + a + a + d = 21 3a = 21 ∴a=7 (a + d) (a - d) a = 315 =(7+d)(7−d)×7=315 =(7 2 −d 2 )=45 =7 2 −45=d 2
=49−45=d 2
=4=d 2
d=±2 numbers are 7 - 2 , 7 , 7 + 2 = 5 , 7 , 9 |
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