Answer
See graph and explanation.
Work Step by Step
(a) It can be clearly seen in the graph of the function that as x approaches $-\infty$, f(x) approaches the x-axis (y=0) and as x approaches $\infty$, f(x) approaches the line y=8.
So the asymptotes are:
y=0 and y=8
(b) The graph of f(x) approaches y=4 on both sides of the y-axis as can be clearly seen in the image.
So the only asymptote is y=4.