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What are the domain and the range of this function? [tex]f(x) = \log(x + 3) - 2[/tex]

A. domain: [tex](-3, \infty)[/tex], range: [tex](-\infty, 2)[/tex]

B. domain: [tex](3, \infty)[/tex], range: [tex](-\infty, 2)[/tex]

C. domain: [tex](3, \infty)[/tex], range: [tex](-\infty, \infty)[/tex]

D. domain: [tex](-3, \infty)[/tex], range: [tex](-\infty, \infty)[/tex]


Sagot :

To determine the domain and range of the function [tex]\(f(x) = \log(x + 3) - 2\)[/tex], let's go through the problem step-by-step:

### Domain:
1. The function includes a logarithm, [tex]\(\log(x + 3)\)[/tex]. The argument of a logarithmic function must be greater than zero.
2. Set the argument [tex]\(x + 3 > 0\)[/tex].
3. Solve for [tex]\(x\)[/tex]:
[tex]\[ x + 3 > 0 \implies x > -3 \][/tex]
4. Therefore, the domain of the function is all values of [tex]\(x\)[/tex] greater than [tex]\(-3\)[/tex]:
[tex]\[ (-3, \infty) \][/tex]

### Range:
1. The logarithmic function [tex]\(\log(x)\)[/tex] by itself can take any real number. That means the range of [tex]\(\log(x)\)[/tex] is [tex]\((-\infty, \infty)\)[/tex].
2. Adding [tex]\(3\)[/tex] inside the logarithm does not affect the range; it translates the function horizontally. Hence, [tex]\(\log(x + 3)\)[/tex] also has a range of [tex]\((-\infty, \infty)\)[/tex].
3. The given function subtracts [tex]\(2\)[/tex] from [tex]\(\log(x + 3)\)[/tex]. Since subtracting a constant will only shift the entire graph downward, it does not impose any limits on the range.
4. Therefore, the range of [tex]\(f(x) = \log(x + 3) - 2\)[/tex] is also all real numbers:
[tex]\[ (-\infty, \infty) \][/tex]

Thus, the correct answer is:

D. domain: [tex]\((-3, \infty)\)[/tex]; range: [tex]\((-\infty, \infty)\)[/tex]