[tex]x = \frac{5}{3} [/tex]
[tex]y = \frac{2}{3} [/tex]
[tex]a) {x}^{ - 1} = { (\frac{5}{3} )}^{ - 1} = \frac{1}{ \frac{5}{3} } = \frac{3}{5} [/tex]
[tex]b)x + y = \frac{5}{3} + \frac{2}{3} = \frac{5 + 2}{ 3 } = \frac{7}{3} [/tex]
[tex]c)y - x = \frac{2}{3} - \frac{5}{3} = \frac{2 - 5}{3} = \frac{ - 3}{3} = - \frac{3}{3} = - 1[/tex]
[tex]d) {y}^{3} = { (\frac{2}{3}) }^{3} = \frac{ {2}^{3} }{ {3}^{3} } = \frac{8}{27} [/tex]