Resposta:
a.
[tex] {4}^{ - 2} = \frac{1}{ {4}^{2} } = \frac{1}{16} [/tex]
b.
[tex] {( \frac{3}{7}) }^{ - 2} = { (\frac{7}{3} )}^{2} = \frac{49}{9} [/tex]
c.
[tex] { (\frac{2}{5}) }^{ - 1} = \frac{5}{2} = 2.5[/tex]
