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October 28th, 2016, 10:34 AM   #1
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Question Arithmetic Progression (AP)

Given that the 8th term of an AP is 5 times the 3rd term and the 7th term is 9 greater than the 4th term, find the first five terms.
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October 28th, 2016, 10:48 AM   #2
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Originally Posted by Hezekiah View Post
Given that the 8th term of an AP is 5 times the 3rd term and the 7th term is 9 greater than the 4th term, find the first five terms.
$a_n = a_1 + (n-1) d$

$a_8 = 5 a_3$

$a_7 + 9 = a_4$

plug in expressions for $a_n$ above and solve for $a_1$ and $d$
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