Answer:
x = -2
Step-by-step explanation:
[tex] {3}^{ - 2x} = 81[/tex]
[tex] {3}^{ - 2x} = {3}^{4} [/tex]
Compare the two exponentials, since the bases are equal then their powers are equal.
-2x = 4 Divide both sides by -2
x = 4/-2