Question

look at the graph:
what is the equation of the horizontal asymptote?

Explanation:

Step1: Recall horizontal asymptote definition

A horizontal asymptote is a horizontal line ($y = k$) that the graph of a function approaches as $x$ approaches $+\infty$ or $-\infty$.

Step2: Analyze the graph's behavior

Looking at the graph, as $x$ approaches $+\infty$ (right - hand side) and $x$ approaches $-\infty$ (left - hand side), the graph of the function approaches the line $y = 0$ (the x - axis).

Answer:

$y = 0$