In order to find the values of f(0), f(1) and f(2), we just need to find in the graph for the value of the function (that is, the value of y) for the values of x equal to 0, 1 and 2 respectively.
Looking at the graph, for x = 0 we have y = -7, therefore f(0) = -7
For x = 1 we have y = -2, therefore f(1) = -2
For x = 2 we have y = -5, therefore f(2) = -5