Answer:
Step-by-step explanation:
The domain is the set of values of x for which the function is defined. Those are the values of x that make the square root argument non-negative:
x -7 ≥ 0
x ≥ 7
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Since the square root cannot be negative, the sum of it and 9 cannot be less than 9. The range is ...
f(x) ≥ 9