Answer:
a32 = -80
Step-by-step explanation:
The generic term of an arithmetic sequence is ...
an = a1 +d(n -1)
Using the supplied values for an and n, we can write two equations that can be solved for a1 and d.
-221 = a1 +d(79 -1)
-14 = a1 +d(10 -1)
Subtracting the second equation from the first, we have ...
-221 -(-14) = (a1 +78d) -(a1 +9d)
-207 = 69d . . . . . simplify
-3 = d . . . . . . . . . . divide by the coefficient of d
Then the value of a1 can be found as ...
-14 = a1 +(-3)(9) . . . . substitute for d in the second equation
13 = a1 . . . . . . . . . . . add 27
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Using our formula to find the 32nd term, we have ...
an = 13 -3(n -1)
a32 = 13 -3(32 -1)
a32 = -80
The 32nd term of the sequence is -80.
