1)
[tex]5^{-8}\times 5^{-4} = 5^{-8 +(-4)} = 5^{-8-4} = 5^{-12}[/tex]
The answer is D
2)
[tex]3^{-6-x} = 3^{4}\\-6-x=4\\x = -10[/tex]
The answer is A
3)
[tex](10^6) ^x = 10^{-18}\\6x = -18\\x=-3[/tex]
The answer is -3
4)
[tex] \frac{5^{-6}\times 5^2 }{5^{-8}} = \frac{5^8 \times 5^2}{5^6} = \frac{5^{8+2}}{5^6} = \frac{5^{10}}{5^6} = 5^{10-6} = 5^4[/tex]
The answer is C
5)
[tex] \frac{5^8}{(5^{-4})^{-3}} = \frac{5^8}{5^{-4\times -3}}=\frac{5^8}{5^{12}}= 5^{8-12} = 5^{-4}[/tex]
Your answer is -4