  We describe a method to compute the Culler-Shalen seminorms of a knot, using
the (-3,3,4) pretzel knot as an illustrative example. We deduce that the
SL2(C)-character variety of this knot consists of three algebraic curves and
that it admits no non-trivial cyclic or finite surgeries. We also summarize
similar results for other (-3,3,n) pretzel knots including the observation that
the Seifert surgeries for these knots are precisely those integral slopes lying
between two of the boundary slopes.
