For this case we have that by definition, the slope of a line is given by:
[tex]m = \frac {y_ {2} -y_ {1}} {x_ {2} -x_ {1}}[/tex]
We need two points through which the line passes.
[tex](x_ {1}, y_ {1}) :( 1,4)\\(x_ {2}, y_ {2}) :( 3,2)[/tex]
Substituting:
[tex]m = \frac {2-4} {3-1} = \frac {-2} {2} = - 1[/tex]
Answer:
[tex]m = -1[/tex]
