Answer:
2 N
Step-by-step explanation:
Neglecting friction, air resistance, and gravitational pull, the force on the backpack feels like 2 Newtons. This is because we have a +6N force towards the right and -4N towards the left (left means negative and right means positive).
Summing them up, we get 2N. Now the total force differs if there are external forces acting on the backpack.