Intermediate Algebra for College Students (7th Edition)

$-4$; $-4$
RECALL: (i) The linear equation $y=mx+b$ has $m$=the slope and $b$=the y-intercept. (ii) Parallel lines have equal slopes. The given equation has $m=-4$, so the slope of the line is $-4$. Thus, any line that is parallel to the given line also has a slope of $-4$.