Since there is no indication of a shift in the graph of f(x) = 3cos(-0.25x), then the midline must be the normal midline for a cosine or sine function which is: y = 0.
The x-intercept of the graph is the x-point where graph touches the x-axis. ... Here graph touches the x-axis two times. (c) (–1, 2) and (1, 0): x-intercept are -1 and -1.