Explanation:
The exponential function is moving from a high value on the y axis to a lower value on the y axis whilst the x values increases from negative to positive x values.
[tex]\begin{gathered} \text{For a function to increase over an interval, as the x values increase the y values also increase} \\ \text{For a function to decrease over an interval},\text{ as the x values increases, the y values decrease} \end{gathered}[/tex]
The arrows at the ends of the exponential function graph indicate from negative infinity to positive infinty.
Hence, it is decreasing on the interval from negative infinity to positive infinity
[tex]\text{The function is decreasing on the interval }(-\infty,\text{ }\infty)[/tex]
