[tex] \frac{ {8}^{ - 2} }{ {4}^{y + 2} } = \frac{128}{ {2}^{ \frac{2y}{3} } } [/tex]

[tex] \frac{ {2}^{ - 6} }{ {2}^{2y - 4} } = \frac{ {2}^{7} }{ {2}^{ \frac{2y}{3} } } \\ - 6 - 2y + 4 = 7 - \frac{2y}{3} \\ - 18 - 6y + 12 = 21 - 2y \\ - 4y = 27 \\ y = - \frac{27}{4} [/tex]