Answer:
The slope should be -1.
----------------------------------
Hope this helps!
Have a great day and God bless! :)
================================================
Work Shown:
[tex](x_1,y_1) = (1,-1) \text{ and } (x_2,y_2) = (2,-2)\\\\m = \frac{y_{2} - y_{1}}{x_{2} - x_{1}}\\\\m = \frac{-2 - (-1)}{2 - 1}\\\\m = \frac{-2 + 1}{2 - 1}\\\\m = \frac{-1}{1}\\\\\boldsymbol{m = -1}\\\\[/tex]
--------------------
Side notes:
Slope = rise/run
rise = change in y value = [tex]y_{2} - y_{1}[/tex]
run = change in x value = [tex]x_{2} - x_{1}[/tex]
Make sure you subtract in the same order each time.