What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: For all x_6, if x_6 were a mechanic, then x_6 is working. For all x_6, x_6 is an artist if and only if x_6 will work. For all x_6, if x_6 were an artist, then x_6 is a mechanic.
For all x_6, if x_6 were an artist, then x_6 is working can be inferred via the universal transitivity rule. For all x_6, if x_6 were an artist, then x_6 is working can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 works, then x_6 is an artist can be inferred via the universal biconditional elimination rule.