Explain, using these theorems, why the function is continuous at every number in its domain. + 2 f( x ) = 4 4 + 4 Of(x) is the sum of two functions that are continuous on the domain of f(x), so it is continuous at ev Of(x) is a rational function, so it is continuous at every number in its domain. O f(x) is the quotient of functions that are continuous on the domain of f(x ), so it is continuous at eve Of(x) is a polynomial, so it is continuous at every number in its domain. Of(x) is not continuous at every number in its domain. State the domain. (Enter your answer using interval notation.) X