Resposta:

[tex]a) {( \frac{2}{3} )}^{ - 2} - {4}^{ \frac{1}{2} } = {( \frac{3}{2} )}^{2} - \sqrt{4} = [/tex]

[tex] = \frac{9}{4} - 2 = \frac{9}{4} - \frac{8}{4} = \frac{1}{4} [/tex]

[tex]b) {1000}^{ \frac{1}{3} } + ( \frac{1}{9} )^{ - 2} = \sqrt[3]{1000} + {9}^{2} = [/tex]

[tex] = 10 + 81 = 91[/tex]

[tex]c) {( \frac{8}{125}) }^{ - \frac{1}{3} } - {( \frac{25}{4}) }^{ \frac{1}{2} } = ( \frac{125}{8} ) ^{ \frac{1}{3} } - {( \frac{25}{4}) }^{ \frac{1}{2} } = [/tex]

[tex] \sqrt[3]{ \frac{125}{8} } - \sqrt{ \frac{25}{4} } = \frac{5}{2} - \frac{5}{2} = \frac{0}{2} = 0[/tex]

Espero ter ajudado.

Bons estudos.