Answer:
a) an = 12 -2(n -1)
b) an = 25 -5(n -1)
Step-by-step explanation:
The n-th term of an arithmetic sequence is given by ...
an = a1 +d(n -1) . . . . . first term a1, common difference d
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a)
The first term is a1 = 12; the common difference is d = 10 -12 = -2.
The n-th term is ...
an = 12 -2(n -1)
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b)
The first term is a1 = 25; the common difference is d = 20 -25 = -5. The n-th term is ...
an = 25 -5(n -1)
