the so-called "zeros" or "solutions" or "roots", are really just the x-intercepts, namely, where the graph touches or "intercepts" the x-axis, look at the graph, goes down and up and down again and up again, and hits the x-axis several times.
29)
what is "c", namely one of those x-values where it touches? look at the graph, it hits at 0.5, 1, 2, 3, pick your poison.
30)
how many? well, you already know.