Answer:

1.      (property a ^-n  =   )

4.        (property a ^-n  =   )

7.      (property   = a ^m-n )

Teacher NoteS:

Students should understand the relationship of how negative exponents impact a number.  Understanding is more than finding the value of numbers derived from a calculator.  Equivalence to 3^-2  is more than finding other representations of .1 repeating (or .111…).  Understanding that negative exponents generate the reciprocation of the number is more important than a numeric solution.