Answer: D) all real numbers greater than or equal to -3
In other words, it's any number that is -3 or larger.
This is because the lowest point occurs when y = -3. We can have y output values that are this or larger. The range is the set of all possible y outputs of a function.
To write the range in interval notation, we write
where the square bracket says "include the endpoint". It's effectively representing the interval
