Answer:
Horizontal asymptote of y=1.
Explanation:
End behavior is talking about limits as x approaches infinity and negative infinity

because substituting large numbers in for x (like a million, billion, or trillion) would give basically a large number over basically the same large number, and anything over itself = 1.

Same reasoning as the last one.
So, x+1/x+3 has a horizontal asymptote of y=1.