College Algebra (10th Edition)

Published by Pearson
ISBN 10: 0321979478
ISBN 13: 978-0-32197-947-6

Chapter 6 - Section 6.2 - One-to-One Functions; Inverse Functions - 6.2 Assess Your Understanding - Page 423: 105


See below.

Work Step by Step

In a one-to-one function, for every $y=f(x)$there is a unique $x$, so by the Horizontal Line Test, if the function is crossed by a Horizontal Line more than once, then there is a $y$ for which there are at least $2$ $x$s, thus it is not one-to-one.
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