Answer:
1
Step-by-step explanation:
using the rules of exponents
[tex]a^{m}[/tex] × [tex]a^{n}[/tex] = [tex]a^{(m+n)}[/tex] , [tex]a^{0}[/tex] = 1 , then
[tex]9^{4}[/tex] × [tex]9^{-4}[/tex]
= [tex]9^{(4+(-4))}[/tex]
= [tex]9^{(4-4)}[/tex]
= [tex]9^{0}[/tex]
= 1
