Question

If the net force on an object is to the left, what will the direction of the resulting acceleration

Answer 1

Acceleration points in the same direction as the net force, so to the left.

The direction of velocity can't be determined from this information alone, though. If the object is at rest, it will being moving to the left. If the object is already moving to the left, it will continue doing so and speed up. If it starts off moving to the right, it will continue to move to the right but eventually slow to a stop before starting to move to the left. There are more cases to consider if you're talking about motion in more than one dimension.