The graph of y=f(x) is shown in red below. For how many values of c is f(c)=-1?
(Assume grid lines are spaced 1 unit apart)
Graph the line x=-1 and count how many times the red graph crosses it.
x=-1 crosses it 4 times, around 3, 1.5, -1.5, and -4.
Thank you so much!