1. ## interval notation

Helpwith finding the domain of
f(x)=7-squar3x+21, and express it using interval notation.
my answer is (-7,infinity). thanks for taking time to check this question.

2. Originally Posted by wayne
Helpwith finding the domain of
f(x)=7-squar3x+21, and express it using interval notation.
my answer is (-7,infinity). thanks for taking time to check this question.
Hello,

if your notation means that the (-7) belongs to the domain too, then your answer is correct.

I'm used to a slightly different notation and I would write it like this: [-7; ∞[ Because ∞ is not a real number the infinity doesn't belong to the domain.

3. ## thats right

thanks, needed another person to look at it also. but yes you are right. thank you very much.

4. Originally Posted by wayne
needed another person to look at it also.
i'm used to seeing the notation

[-7 , ∞)

we use square brackets to show inclusion and parentheses to show exclusion