Answers

2016-06-21T20:21:30+08:00
#6. A1=3 D=4 An=59 n=15
solution: An=A1+(n-1)d
59=3+(n-1)4
59-3+4=4n
60/4=4n/4
15=n
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2016-06-21T22:09:03+08:00
#5  An=A1+(n-1)d

A8=54   d=6  A9=60  n=8


A8=A1+(8-1)(6)
54=A1+(7)(6)
54=A1+42

54-42=A1+42-42 => SUTRACT both sides by 42 to get the value of A1

12=A1  or  A1=12

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