Solve on the domain 0° ≦ x ≦ 360°. Use a calculator and round to the nearest degree if unable to use special triangles.

cos x-1 = -cos x

Can anyone give me some pointers on this one? I'm taking grade 12 math through an independent learning course, where I have no access to a teacher, and this question has me completely stuck.

I've solved other trig equations by isolating x and using a special triangle, a calculator, or simply looking at the graph sometimes. However, the right side of the equation has always been a real number in the past, and I'm not sure what to do with this -cos x.