What best compares the graphs y=-3x^n and y=3x^n

The graph of y=-3x^n is the reflection of the graph of y=3x^n about the y axis

Explanation:

Name: f(x) = - 3 x^n and g(x) = 3 x^n. then f(x) = - g(x).

That means that for a given value of x the output of g(x) is the negative of the value of f(x), which is what you obtain when you reflect the function g(x) across the x axis.