For f(x)=9x+9 and g(x) = x, find the following composite functions and state the domain of each. (a) fog (b) g of (c) fof (d) gog answers as needed.) B. The domain of fog is all real numbers. (b) (go f)(x) = 81x +162x+81 (Simplify your answer.) Select the correct choice below and, if necessary, fill in the answer box within your choice. OA. The domain of g of is {x}. (Type an inequality. Use integers or fractions for any numbers in the expression. Use a comma to separate answers as needed.) B. The domain of g of is all real numbers. (c) (fof)(x)=81x+90 (Simplify your answer.) Select the correct choice below and, if necessary, fill in the answer box within your choice. OA. The domain off of is {x}. (Type an inequality. Use integers or fractions for any numbers in the expression. Use a comma to separate answers as needed.) B. The domain of f of is all real numbers.