So we have this
16 ≥ x^2 + y^2 ≤ 25
Taking this in pieces, we have
x^2 + y^2 ≤ 16 and x^2 + y^2 ≤ 25
Here's the graph of both........https://www.desmos.com/calculator/svaaytcslp
Note that the "solution" is the "blue area" inside the "red area".....and this is just the graph of x^2 + y^2 ≤ 16.....!!!!