ANSWER
C. x=7
EXPLANATION
The given exponential equation is
[tex] {3}^{x - 5} = 9[/tex]
We rewrite the right hand side as 3 raised to exponent 2.
[tex] {3}^{x - 5} = {3}^{2} [/tex]
Observe that the base of both sides of the equation are equal.
We now equate the exponents.
[tex]x - 5 = 2[/tex]
Solve for x,
[tex]x = 2 + 5[/tex]
[tex]x = 7[/tex]
The correct choice is C.