Let's put more details in the given figure to better understand the problem:
In a function, f(x) = y. This means that the function means at given x, y is the result or output of the function.
a.) At f(-2), we are asked what is the y equivalent of the function at x = -2.
Looking at the graph, we've determined that at x = -2, y = 2.
Therefore, f(-2) = 2
b.) Finding one value of x for which f(x) = 4. This means that we are asked what is the x equivalent of the function will have a y equivalent of 4.
From the graph, 4 appears to be a vertex of the parabolic graph. And the x at y = 4 is at the origin which is equal to 0.
Therefore, we can say, that at y = 4, x = 0.
Answer: f(x) = 4, x = 0