(a) The graph in Figure 1 is not a function of x (b) The graph in Figure 2 is not a function of x
Work Step by Step
(a) A function can only have one value f(x) for each x in it's domain. From this graph we can see that if we were to draw vertical lines, some vertical lines would intersect the graph twice at certain x values. Hence this is not a function. (b) Same reasoning as part a, a vertical line drawn in this graph has more than one intersection, this means that not every x value has a single y value output.