1). To determine f(-1), we must first know (-1)197 and (-1)248. You should never multiply out lots of numbers.
2). Instead, look for a pattern:
(-1)1=-1
(-1)2=+1
(-1)3=-1
(-1)4=+1
...
(-1)(odd number)=-1
(-1)(even number)=+1
3).This means (-1)197=-1 since 197 is odd and (-1)248=+1 since 248 is even.
4).This pattern simplifies the equation to:
-5(-1) - 8(1) + 1, which equals 5 - 8 + 1, or -2.
Thus, C is the correct answer.
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