Hello there!
We are given the function:

To find the range, we know that domain is the set of all x-values and also called 'input' while range is the set of all y-values and also called 'output'.
Basic Function - you add the input, you get the output. You add x-value in a function, you get y-value. You add domain, you get range.
So, we substitute x = 1,2 and 3 in the function.
<u>x</u><u> </u><u>=</u><u> </u><u>1</u>

Recall that any numbers in absolute value are always positive.

<u>x</u><u> </u><u>=</u><u> </u><u>2</u>

<u>x</u><u> </u><u>=</u><u> </u><u>3</u>

Therefore, Range: {-1,1,3}
Let me know if you have any questions!
Topic: Absolute Value Function / Modulus Function