The domain of a function represents the range of x-values that are part of the function, read left to right. We can see that the function goes forever to the left and stops at when we read left to right. Therefore, the domain of this function is .
The point at is a filled-in solid dot so it is included as part of the function. Use square brackets to denote inclusive.
The range of a function represents all y-values that are part of the function, read bottom to top. The function continues down forever and stops at when read bottom to top. Therefore, the range of this function is . Similar to the domain, we use a square bracket on the right to indicate that is included in the function. If the dot was not filled-in, then we would use a parenthesis to indicate that would not be part of the function.
