So, we first remember that the range of a function is the set of all resulting values of the y variable. In a graph, it could be represented as all the values on the vertical line seen on the function.
Also, we have to remember the intervals we will use for defining it. If the function touches the value we use the [ parenthesis for that value, and if it doesn't, we use the ( parenthesis.
We see that the function has the values from 1 to 5. On the x-value 0, f(0)=1 and it touches the point. But, at -4 we see a hollow circle, which means that the function doesn't meet the value 5.
This gives us an idea: the range goes from 1 to 5, touching 1 and not touching 5.
So, we use a [ parenthesis for 1, and a ( parenthesis for 5. This would mean that:
