Answer:
x = 6
Step-by-step explanation:
Using the rule of exponents
[tex]a^{m}[/tex] × [tex]a^{n}[/tex] ⇔ [tex]a^{(m+n)}[/tex] , then
[tex]3^{-2}[/tex] × [tex]3^{x}[/tex] = 81 , that is
[tex]3^{x-2}[/tex] = [tex]3^{4}[/tex]
Since the bases on both sides are equal, both 3 then equate the exponents
x - 2 = 4 ( add 2 to both sides )
x = 6
