Hi there!
An equation in the slope-intercept form is written as :
y = mx + b
Where "m" is the slope of the line and "b" is the y-intercept.
Your equation is :
y = -5x - 1
Where you can see that the number in the place of "m" is -5, which is the slope of the line.
Answer : The slope of the line is -5.
There you go! I really hope this helped, if there's anything just let me know! :)