SOLUTION
(c) The values of x for which f(x) = -1
Looking from the graph, this does not exist.
Hence the answer is "None"
(d) The values of x for which f(x) = -3
Looking form the graph, this is between 0 and 1
So we have this as

So in interval notation, the answer is

(e) The x-intercept is where the graph cuts the x-axis
The graph cuts the x-axis at -1
Hence the answer is (-1, 0)