When solving these proportions we just remember when moving a number from one side to the other if it started in the numerator it ends up in the denominator and vice versa.
I'll do it in two steps here for teaching purposes; it's not too hard to go directly to the answer.
Answer:
B. -6 does not belong to the domain but belongs to the range of f(x).
Step-by-step explanation:
We have the function, .
So, the domain of the function is obtained when i.e.
That is, the domain is {x | x≥ 7}.
Now as we have,
→
→
→
→
.
That is,
Thus, the range of the function f(x) is {y | y≤ 1}.
Thus, we can see that,
-6 does not belong to the domain but belongs to the range of f(x).