I'll just do the first one.
Factor the numerator and denominator:
Setting the denominator = 0, 3x(x-3) = 0, tells us that
we have discontinuities at x=0, and at x=3
We must decide which type of discontinuity we have at 0 and 3.
1. If we can cancel a common factor in the numerator and denominator
and remove the discontinuity, then it is a "removable discontinuity"
or "a hole in the graph".
2. If we can't cancel a factor, then the discontinuity is infinite and
there is an asymptote there.
We have one of each type.
1. We can remove the discontinuity at x=0 by cancelling the x in the
numerator and denominator. To find out where the hole is, we cancel
the x and get a new function which is like the original function everywhere
except at the hole. Let's call it g(x):
g(x) doesn't have a hole at x=0, we substitute and find
So f(x) has a hole at
2. We cannot remove the discontinuity at x=3 by cancelling, so there is
a vertical asymptote there, a "non-removable" discontinuity.
Since the degree of the numerator and denominator have the same degree, 1,
there is a horizontal asymptote at y = the ratio of the two leading
coefficients, so the horizontal asymptote has equation y=1/3,
So we plot the hole at , the vertical asymptote at x=3, and the horizontal
asymptote at y=1/3:
Edwin