Answer:
-4
Step-by-step explanation:
[tex]\left( \dfrac{1}{9}\right)^{a+1}= 81^{a+1}\cdot 27^{2-a}\\\\\\(3^{-2})^{a+1}=(3^4)^{a+1}\cdot (3^3)^{2-a} \\\\\\3^{-2a-2}=3^{4a+4}\cdot 3^{6-3a} \\\\\\3^{-2a-2}=3^{a+10} \\\\\\-2a-2=a+10 \\\\\\-3a=12 \\\\\\a=-4[/tex]
Hope this helps!
