how can I solve this problem?

Below is the graph of a function f(I). 9 10 -9 -8 -7 7-6 -4 -3 -2 For both questions below, round all answers to the nearest integer. If there is more than one correct answer for either question, then list all answers in the answer box with commas separating them. If there is no answer, or if the answer is impossible to determine from this graph, then type "DINE" (which stands for "does not exist"). (a) What is the value of f(6)? f(6) = (b) What are the value(s) of x for which f(z) = -1