#6, #8, #20, #28, #30, #47.
#56. (Hint: look at your class notes from Thursday 10/26.)
#9, #17, #45, #49, #50, #51, #52, #55, #56, #57, #58.
#64. (One key point you need to explain is why
S1 is also a spanning set of V.)
#2, #7, #15, #16, #23, #24.