Final answer:
If an object is traveling east and slowing down, its acceleration is westward or negative when east is considered positive. This negative acceleration is indicative of deceleration.
Step-by-step explanation:
If an object is traveling east with a decreasing speed, the direction of the object's acceleration is to the west. Acceleration is defined as the rate of change of velocity. If an object is slowing down, its acceleration is in the opposite direction of its velocity. When we consider east as the positive direction, and the object is moving east but slowing down, it means the object has a negative acceleration because it is accelerating toward the west. This is often referred to as deceleration. A real-world example could be an airplane landing on an eastward facing runway; as it comes to a stop, it experiences negative acceleration.