ANSWER:
[tex]\lbrack\frac{6^{10}}{7^6}\rbrack[/tex]EXPLANATION:
Given:
[tex]\lbrack\frac{6^5}{7^3}\rbrack^2[/tex][tex]\begin{gathered} \lbrack\frac{6^5}{7^3}\ast\frac{6^5}{7^3}\rbrack \\ \text{law of indices:} \\ \lbrack\frac{A^x}{B^x}\rbrack^y\text{ = }\lbrack\frac{A^{x\ast y}}{B^{x\ast y}}\rbrack \end{gathered}[/tex][tex]=\text{ }\lbrack\frac{6^{5\ast2}}{7^{3\ast2}}\rbrack\text{ = }\lbrack\frac{6^{10}}{7^6}\rbrack[/tex]