[tex]y = mx + b[/tex]
where m = slope and b = y-intercept.
We have both given slope and y-intercept. We can simply substitute the given slope and y-intercept in slope-intercept form.
Substitute m = -1 and b = - 5 in the equation.
[tex]y = - 1x - 5 \\ y = - x - 5[/tex]
We don't usually write 1x or -1x instead we write -x or x.
[tex]y = - x - 5[/tex]