8)
Check the picture below on the left-side
so f(x) = 0, or what's "x" when y = 0? well, when y = 0 x = 1, as you can see in the picture.
9)
Check the picture below on the right-side
so g(x) = 3, what's "x" when y = 3?
well, notice, the graph of g(x) never goes above -1 or y = -1, doesn't even make it to y = 0, let alone to y = 3, so what's "x" when y = 3? well, N/A or we can say "x is undefined" or simply doesn't exist.