We have that equation of the line in point-slope form is
[tex]y-y_1=m(x-x_1)[/tex]
where m is the slope and (x1,y1) is a point where the line passes through
in our case
m=-1
(x1,y1)=(-5,-3)
we substitute the values
[tex]y+3=-1(x+5)[/tex]
then we simplify
[tex]y+3=-x-5[/tex]
then we isolate the x and we obtain the equation of the line
[tex]y=-x-8[/tex]
