Consider the following premises. For all x_8, x_8 will not drive a car. For all x_8, x_8 will drive a car if and only if x_8 is an artist. For all x_8, x_8 is happy if and only if x_8 is an artist. For all x_8, if x_8 were an artist, then x_8 is happy. Can we infer the following from them? If we can, name the inference rule being used: For all x_8, x_8 is not happy.
 From the fact that for all x_8, x_8 is happy if and only if x_8 is an artist we can infer that for all x_8, if x_8 were happy, then x_8 is an artist via universal biconditional elimination. From the fact that for all x_8, x_8 will drive a car if and only if x_8 is an artist, and that for all x_8, x_8 will not drive a car we can infer that for all x_8, x_8 is not an artist via universal biconditional elimination. From the fact that for all x_8, if x_8 were an artist, then x_8 is happy, and that for all x_8, if x_8 were happy, then x_8 is an artist we can infer that for all x_8, x_8 is an artist if and only if x_8 is happy via universal biconditional introduction. Finally, from the fact that for all x_8, x_8 is an artist if and only if x_8 is happy, and that for all x_8, x_8 is not an artist we can infer that for all x_8, x_8 is not happy via universal biconditional elimination. Therefore, the answer is yes.