Answer
$$
m=-\frac{2}{5}
.$$
Work Step by Step
Rewrite the equation in the slope-intercept form $y=mx+c$ as follows:
$$
5y=-2x+8\Longrightarrow y=-\frac{2}{5}x+\frac{8}{5}
.$$
Now, by comparing the given equation with the standard slope-intercept form $y=mx+c$, we find that the slope is
$$
m=-\frac{2}{5}
.$$
