Perform the Operations and Simplify the Result When Possible $\frac { 2 } { a b ^ { 2 } } - \frac { 3 } { a ^ { 2 } b }$

Essay

Perform the operations and simplify the result when possible. $\frac { 2 } { a b ^ { 2 } } - \frac { 3 } { a ^ { 2 } b }$