ASSUMING THAT THE FUNCTION IS SYMMETRICAL:
This graph is identical if it is the same when "reversed." x represents the coordinate in the x-axis, while f(x) represents the coordinate in the y-axis.
If
x = -1, then f(x) = 1
x = -3, then f(x) = 2
x = -5, then f(x) = 3
x = -6, then f(x) = 3