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# is the domain for f(x) = 1/2(x+3) all real numbers?

Math question

the 3 is in the numerator - it's (1/2)(x+3) - so, it's all real, correct?

### 3 Answers

- Randy PLv 79 years agoFavorite Answer
Depends on whether that (x + 3) is in the numerator or the denominator.

If it's in the numerator, yes.

If it's in the denominator, no. You can't divide by 0, and there is a real number which makes x + 3 equal to 0.

- Eclipse-girlLv 79 years ago
No. x cannot equal - 3. then the denominator would equal zero.

Whenever you deal with fractions, you can't have the denominator ever equal zero

so the domain is (- infinity, -3) U (-3, infinity)

The round parentheses indicate everything up to but not including that value, kind of like a < or > symbol. A square bracket [ or ] indicates the the value is included.

We use round parenthesis for infinity because of convention. We never get to infinity, there is always more out there.

In this example, -3 in not included.

- Anonymous9 years ago
no -3 is not in the domain