Science and Mathematics for Engineering 6th Edition by John Bird

Exercise 6

Evaluate: (a) $( 27 ) ^ { - \frac { 1 } { 3 } }$

$\text { (b) } \frac { \left( \frac { 3 } { 2 } \right) ^ { - 2 } - \frac { 2 } { 9 } } { \left( \frac { 2 } { 3 } \right) ^ { 2 } }$