Yes it is. In order for something to be a function, no X values can be the same, which is the case here.
Answer:

General Formulas and Concepts:
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<u>Algebra I</u>
<u>Algebra II</u>
- Distance Formula:

Step-by-step explanation:
<u>Step 1: Define</u>
<em>Identify</em>
Point (21, 13)
Point (3, 13)
<u>Step 2: Find distance </u><em><u>d</u></em>
Simply plug in the 2 coordinates into the distance formula to find distance <em>d</em>
- Substitute in points [Distance Formula]:

- [√Radical] (Parenthesis) Subtract:

- [√Radical] Evaluate exponents:

- [√Radical] Add:

- [√Radical] Evaluate:

Answer:
b) 16 rt 2
Step-by-step explanation:
using the 45-45-90 triangle trick,
let x=16
then BC is x rt 2, or 16 rt 2