Respuesta :

For this case we have the following expression:
 (ab) ^ - 2
 Rewriting the expression we have:
 (ab) ^ - 2 = 1 / (ab) ^ 2
 Then, for power properties we have:
 1 / (ab) ^ 2 = 1 / (a ^ 2b ^ 2)

 Answer:
 The simplified expression is:
 
1 / (a ^ 2b ^ 2)