Consider the following premises. If Robert drives a car, then Susan is a poet. Susan is a poet if and only if Robert is a writer. If Susan were a poet, then Robert is driving a car. Can we infer the following from them? If we can, name the inference rule being used: If Robert drives a car, then Robert is a writer.
 From the fact that if Susan were a poet, then Robert is driving a car, and that if Robert drives a car, then Susan is a poet we can infer that Susan is a poet if and only if Robert is driving a car via biconditional introduction. From the fact that Susan is a poet if and only if Robert is a writer we can infer that if Susan were a poet, then Robert is a writer via biconditional elimination. From the fact that Susan is a poet if and only if Robert is driving a car we can infer that if Robert drives a car, then Susan is a poet via biconditional elimination. Finally, from the fact that if Robert drives a car, then Susan is a poet, and that if Susan were a poet, then Robert is a writer we can infer that if Robert drives a car, then Robert is a writer via transitivity. Therefore, the answer is yes.