Consider the following premises. If Linda were rich, then Susan is bored. If Susan were a taxi driver, then Linda is rich. For all x_10, if x_10 were bored, then x_10 is a taxi driver. Can we infer the following from them? If we can, name the inference rule being used: If is not true that Linda is rich if and only if Susan is bored.
 From the fact that for all x_10, if x_10 were bored, then x_10 is a taxi driver we can infer that if Susan were bored, then Susan is a taxi driver via universal instantiation. From the fact that if Susan were bored, then Susan is a taxi driver, and that if Susan were a taxi driver, then Linda is rich we can infer that if Susan were bored, then Linda is rich via transitivity. Finally, from the fact that if Linda were rich, then Susan is bored, and that if Susan were bored, then Linda is rich we can infer that Linda is rich if and only if Susan is bored via biconditional introduction, which contradicts that If is not true that Linda is rich if and only if Susan is bored. Therefore, the answer is no.