select all of the following expressions that are equivalent to 9 1/2
(1) 3 1/2 * 3 1/2 (2) sqrt[6]{27} (3) 27 1/3 * 3 1/2 (4) 81 1/2 * 81 1/2 (5) 729 1/6 (6) 81 1/3 * 81 1/3 (7) 81 1/4 * 81 1/4