For f(x)=6x+7 and g(x) = x, find the following composite functions and state the domain of each. (a) fog (b) gof (c) fof (d) gog (Simplify your answer.) (a) (fog)(x) = 6x+7 Select the correct choice below and, if necessary, fill in the answer box within your choice. A. The domain of fog 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 fog is all real numbers. (b) (go f)(x) = 36x + 84x+49 (Simplify your answer.) Select the correct choice below and, if necessary, fill in the answer box within your choice. A. 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.