Let positive be west and negative be east because they are contrasting in directions.
The forces are 4100, -830, and -1200
The sum of the forces is 4100 – 830 – 1200 = 2070 N.
Newton’s law F = ma is used.
2070 = 6800 a
Isolating a will give us 2070 / 6800 = a
a = 0.34 m/s^2