Chapter 4 - Exponential Functions - 4.3 Graphs of Exponential Functions - Exercises and Problems for Section 4.3 - Exercises and Problems - Page 161: 4

This function is not exponential.

The issue is that the rate of change varies for different $x$. Around $x=0$, the function is decreasing. At larger values of $x$, the function is decreasing. This variability of rate of change means that it cannot be exponential.