The initial problem is:
[tex](3^2\times7^4)^5[/tex]We can use the following property:
[tex](X^a\times Y^b)^c=X^{a\cdot c}\times Y^{b\cdot c}[/tex]So, the initial problem is equivalent to:
[tex]\begin{gathered} (3^2\times7^4)^5=3^{2\cdot5}\times7^{4\cdot5} \\ (3^2\times7^4)^5=3^{10}\times7^{20} \end{gathered}[/tex]Then, solving 3^10 and 7^20, we get:
[tex]\begin{gathered} 3^{10}=59049 \\ 7^{20}=7.98\times10^{16} \end{gathered}[/tex]So, the answer is:
[tex](3^2\times7^4)^5=59049\times7.98\times10^{16}=4.71\times10^{21}[/tex]