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f(x) has the domain 4-x^2 >= 0, where the expression under square root is non-negative.
It is the same as x^2 <= 4, or |x| <= 2, or -2 <= x <= 2.
g(x) has the domain 9-x^2 >= 0, where the expression under square root is non-negative.
It is the same as x^2 <= 9, or |x| <= 3, or -3 <= x <= 3.
For function f(x)/g(x), the domain is the intersection (the common part)
of the two above mentioned domains.
This intersection is the smaller domain |x| <= 2, or -2 <= x <= 2. ANSWER
Solved, with complete explanations.