Question

1. Use the sequence 3, -6, 12, -24, … to answer the questions below
a. Explain, using complete sentences whether this sequence is arithmetic or
geometric and why.
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I guessed its geometric but if thats the answer why is it?

Answer 1

the answer is a

Answer 2

in an arithmetic sequence, the next number is found by adding. In a geometric sequence, the next number is found by multiplying.
so lets look at your sequence : 3, -6, 12, -24
what has to be done to 3 to get -6....3 x -2 = -6
will that same process work for the next number ?
-6 x -2 = -12....and the next...12 x -2 = -24
so the next number was found by multiplying making it a geometric sequence.

Now if you would have tried addition..
3 + ? = -6
3 + (-9) = -6
and if we take that -9 and add it to the next number, do we get the number after that ?
-6 + (-9) = -6 - 9 = - 15...not the next number....so it is not arithmetic.

Understand ?

Answer 3

oops...there is a typo in there....-6 x -2 = 12