The definition of the graph of a function f in the
xy−plane is the set of all points
(x,f(x)). Thus, for
−4≤a≤4, the value of
f(a) is 1 if and only if the unique point on the graph of f with x-coordinate a has y-coordinate equal to 1. The points on the graph of f with x-coordinates
−4,, and 3 are, respectively,
(−4,1),(,1) and
(3,1).Therefore,all of the values of f given in I,II and III are equal to 1
Choices A, B, and C are incorrect because they each omit at least one value of x for which
f(x)=1.