Answer:
A. f(x) = 0.8 (5)ˣ
Explanation:
This is the only one that fits the x and f(x) values
x 0.8 (5)ˣ
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1 0.8 x 5¹ = 0.8 x 5 = 4
2 0.8 x 5² = 0.8 x 25 = 20
3 0.8 x 5³ = 0.8 x 125 = 100
4 0.8 x 5⁴= 0.8 x 625 = 500
The others will not eve yield proper results for x = 1, you can try them out