(d) How often does the line y = 1/2 intersect the graph?
a.) f(8) is asking what the y value is at x = 8; we are given (8, -2), so at x = 8, y = -2. From this information, do you think f(8) is positive or negative? It should be self explanatory. In fact, on the interval from x = -6 to x = 11, the only time the graph is negative is between x = 6 and x = 10.
b.) Nice, I practically answered this answer in a. Take all the other values and you have when f(x) > 0.
c.) This question is asking when is x = 0 and when is y = 0. Just by looking at the graph and seeing when the graph goes through the x and y-axis, you should be able to answer this question. Or, just look at the points, and see when the x or y values are 0.
d.) y = 1/2 is a horizontal line. Draw a horizontal line at y = 1/2.