what is the domain of f(x)=x-5 in interval notation

Question

I dont understand how to find the domain and range ¹11111111111111111111111111111111111@@@@#@@@@@@@@@#%%$#@@%-%12355

Answer 1

Calm down Larry.  We got this.

 

f(x)=x-5 is a linear function, so there are no restrictions to what x can be.  The domain is all real numbers.  In interval notation, we show that is can be anything from negative infinity through infinity like this:

 

(-∞,∞)

This says that the lower limit of the domain is negative infinity and the upper limit is positive infinity.  We use the soft brackets ( and ) which means up to but not including the number because infinity is not an actual solid number, so it can't technically be included.

 

An example of where you would us a hard bracket, [ or ] is in this function:

f(x)=√x

You can't square root a negative number, but it is OK to square root zero, so the domain is everything from 0 up, including 0.  We would show this like this:

[0,∞)

 

Hope this helps.

Answer 2

Hey Larry. Sounds like you could use a refresher on the definitions of domain and range, and how to go about finding them for a specific function. Would you like me to help you? :)