Question 1113334
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Your statement of the problem is not right.  f(x) is the function; it is not the real number you start with.<br>
start with a real number x.
(1) multiply by 2: 2x
(2) subtract 4: 2x-4
(3) take the square root: sqrt(2x-4)<br>
Answer: f(x) = sqrt(2x-4)