9514 1404 393
Answer:
3. 1.8
4. 66
Step-by-step explanation:
3.
The common difference is the difference between a term and the one before it.
5 -3.2 = 1.8
The common difference is 1.8.
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4.
The 8th term is found by putting 8 where n is and doing the arithmetic.
a₈ = 10·8 -14
a₈ = 80 -14 = 66
The eighth term is 66.
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Additional comments
The difference is only "common" if all pairs of adjacent terms have the same difference. When that is the case, any pair of adjacent terms can be used to find the common difference. The arithmetic is probably easier using ...
6.8 -5 = 1.8
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In question 4, the sequence has a first term of -4 and a common difference of 10. The sequence is ...
-4, 6, 16, 26, 36, 46, 56, 66 . . . . the 8th term is 66.
