In a sequence of numbers, each term except the ﬁrst is 4 less than 4 times the previous term. If the fourth term in this sequence is 12, what is the ﬁrst term?

Question

Pablo Franco

Mathematics

20 May, 02:52

In a sequence of numbers, each term except the ﬁrst is 4 less than 4 times the previous term. If the fourth term in this sequence is 12, what is the ﬁrst term?

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Sophia · Answer 1

First term is - 1 because the common difference between each term 4n-4 where n is the term before. Therefore of you work backwards by taking 4 away from 12 then diving by 4 you should get 4 as third term. So you can keep going back till first term and you would get the following sequence

-1, 0, 4, 12 ...