Answer: Choice (4) which is y > 0
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Explanation:
As x heads off to negative infinity, the value of y = 4^x slowly approaches y = 0. It never actually gets to y = 0 even if it looks like it might.
Note that for negative x values, y = 4^x is going to involve a fraction
Example: if x = -2 then y = 4^x = 4^(-2) = 1/(4^2) = 1/16 = 0.0625
So this means that y can be any positive number with 0 being the boundary or fence it runs into. This "fence" is the horizontal asymptote.
