Answer:
It's been a while since I did one of these but I'm pretty sure it's 2.
Explanation:
To determine a line's slope, subtract the second number in each coordinate.
-5 - 1 = -6
Then subtract the first numbers in each coordinate.
1 - 4 = -3
Finally taken the answer to the first equation and put it over the answer to the second equation.
-6/-3
There's your answer, of course you should simplify it. To do this divide -6 by -3.
-6/-3 = 2
Please take this with a grain of salt, it's been a while since I did this.