I need two answers please help me Thank youu

Let the closed interval [a , b] be the domain of function f. the domain of f(x - 3) is given by (a) the open interval (a , b) (b) the closed interval [a , b] (c) the closed interval [a - 3 , b - 3] (d) the closed interval [a + 3 , b + 3]

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If f(x)= sqrt4x+9+2, which inequality can be used to find the domain of f(x)?