Answer:
(1) i and ii
Explanation:
You want the formulas that describe a sequence that starts at $30,000 and increases by $800 each year.
Arithmetic sequence
The initial value of the sequence is 30,000. This is the value for n=0. This rules out choice iii, which has an initial value of -30,000.
When n=1, the value is 30800. This matches the behavior of the formulas in choices i and ii.
(1) i and ii
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Additional comment
The explicit formula for an arithmetic sequence with an initial value of a0 and a common difference of d is ...
an = a0 +nd
The recursive formula for the same sequence is ...
f(n) = f(n-1) +d where f(0) = a0
Here, we are numbering the terms starting with n=0. The salary is increased by 800 to 30,800 after one year, when n=1. Quite often it is the case that the first term of the sequence corresponds to n=1.