Okay so I assume it is the "all and only those" that is confusing you. Remember not to look at these sentences as formulas. You need to take them in context. So, the sufficient condition of this statement is: "raises revenue AND burdens all and only those persons targeted by the tax," while the necessary condition is "a tax is effective"
So we diagram the first sentence:
P1: RR & BAOTT ==> TE not TE ==> not RR or not BAOTT
"A tax is ineffective, however, if it does not raise revenue and it costs a significant amount of money to enforce."
P2: not RR & CSME ==> not TE TE ==> RR or not CSME
Hope that helps! Please let us know if you have any other questions.
