The graph of y=f(x) is shown in red below. For how many values of c is f(c) = -1?
image: https://latex.artofproblemsolving.com/7/4/5/745692871d4963aedcef20352e362e9107ab1ec0.png \(\) (Assume grid lines are spaced 1 unit apart.)
We're looking for values of x where the y point is -1. Looking at the graph, we draw a horizontal line for y=-1. There are 4 values of f(c)=-1.