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the sum of 4th and 8th term of Ap is 24 and the sum of 6th and 10th term is 44find the three term of AP |
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Answer» Step-by-step explanation: Given:-The sum of 4th and 8th term of Ap is 24 and the sum of 6th and 10TH term is 44. To find:-Find the three terms of the AP? Solution:-We know that a is the FIRST term and d is the common difference of an AP then nth term = an = a+(n-1)d 4th term of the AP = a4 = a+(4-1)d a4 = a+3d 6th term = a6 = a+5d 8th term = A8 = a+7d 10th term = a10 =a+9d Now Sum of 4th and 8 th terms = 24 => a4+a8 = 24 =>a+3d+a+7d = 24 =>2a+10d = 24 =>2(a+5d) = 24 =>a+5d = 24/2 a+5d = 12------------(1) and Sum of 6th and 10th terms = 44 =>a6+a10 = 44 =>a+5d+a+9d = 44 =>2a+14d =44 =>2(a+7d)=44 =>a+7d = 44/2 a+7d = 22---------(2) On Subtracting (1) from (2) then a+7d = 22 a+5d = 12 (-) ________ 0+2d = 10 _________ =>2d = 10 =>d = 10/2 =>d = 5 On Substituting the value of d in (2) then =>a+7(5)=22 =>a+35 = 22 =>a = 22-35 =>a = -13 We have a = -13 and d = 5 The first three terms of the AP are a,a+d,a+2d a= -13 a+d = -13+5 = -8 a+2d = -13+2(5)=-13+10=-3 Answer:-The first three terms of the given AP are -13,-8,-3 Check:-a4 = a+3d = -13+4(5)=-13+20=7 a8 = a+7d = -13+7(4)=-13+28=15 a4+a8 = 7+15 = 22 a6 = a+5d = -13+5(5)=-13+25=12 a10=a+9d = -13+9(5)=-13+45 = 32 a6+a10=12+32=44 Verified the given relations. Used FORMULAE:-
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