Step-by-step explanation:
Change 27 to 3^3, and change 9 to 3^2 to get:
[tex] { ({3}^{3} )}^{x} = { ({3}^{2}) }^{x - 4} [/tex]
Multiply the exponents according to exponential rules:
[tex] {3}^{(3x)} = {3}^{(2x - 8)} [/tex]
Same bases, so set exponents equal to each other:
[tex]3x = 2x - 8[/tex]
Subtract 2x on both sides to get:
[tex]x = - 8[/tex]