The range of a function is the set of possible outputs we can get from it. In this case, we have a function f(x) = 2x + 7, f(x) can take the value of any real number, then the range of this function is
(-∞, ∞). In order to get the range of the given domain we just have to put each domain value into the function and calculate the corresponding range value, like this:
domain: {1, 3, 5}
At x = 1
f(1) = 2(1) + 7 = 2 + 7 = 9
At x = 3
f(3) = 2(3) + 7 = 6 + 7 = 13
At x = 5
f(5) = 2(5) + 7 = 10 + 7 = 17
Then, the range of the given domain is {9, 13, 17}
