Question

Look at the following graph of the given equation. Determine whether the equation is the function. Explain why or why not.

Answer 1

Explanation:

It is a function. Every x has only 1 y associated with it. You cannot find an exception to this rule.

Stated another more common way: if you take a ruler and lay it flat on the graph so that the ruler is parallel to the y axis, you will find the ruler will go through only one y for every x. That's called the vertical line test.