What is the sum of the solutions of 2x [×-1]-4=-2

Lets get stated :)

2x ( -1 ) - 4 = - 2
- 2x - 4 = - 2

Bring 4 to the right-hand side { You do addition to the opposite }
- 2x = - 2 + 4
- 2x = 2

Take - 2 to the other side in order to isolate x { Do division when you see multiplication }

x = -1

Quick check:
2 ( - 1 ) ( - 1 ) - 4 = - 2
2 - 4 = - 2
- 2 = - 2
So it is the correct value