Trig Identity Homework Help

I'm looking at a problem and I'm stumped:

(1-tan x) / (sin x-cos x)

I'm trying to reduce it down and can't figure out the trig identity to use to break it down.

Any help?

(1-tan x) / (sin x-cos x)
(1- [sinx/cosx]) / (sin x-cos x)
({cosx- sinx}/cosx]) / (sin x-cos x)
-1/cosx
-secx //Ans