Increasing and Decreasing Functions

A function is decreasing if its graph falls from left to right. Observe that the trend is decreasing for lines with negative slopes. Note also that a function is decreasing if for any two points $\left(x_1,y_1\right)$ and $\left(x_2,y_2\right)$ in the interval, $y_1>y_2$ whenever $x_1<x_2.$ Refer to the figure below.