Resposta:

[tex] {( \frac{2}{3} - 1)}^{2} - {( - 1)}^{2} \\ \\ ( { - \frac{1}{3}) }^{2} - 1 \\ \\ \frac{1}{9} - 1 \\ \\ \frac{1 - 9}{9} \\ \\ \frac{ - 8}{9} \\ \\ = - \frac{8}{9} [/tex]