Hi there, I'm trying to do this question but I'm stuck:

Graph the function:

f(x) = (2/3)^{x}, -4≤x≤1, x∈R

f(-2) lies in the range [1, a]. If a ∈ N, then what is the minimum value of a?

I've drawn the graph, but I don't understand the second part of the question. Could someone please help me?