Final answer:
A decrease in the price of tablet computers, which are a substitute for laptops, is likely to cause a decrease in demand for laptops, represented by a leftward shift in the demand curve for laptops.
Step-by-step explanation:
The most likely effect of the decrease in the price of tablet computers on the market for laptop computers, which are a substitute, is a decrease in demand for laptops. This economic phenomenon happens because consumers will opt for the less expensive tablets, leading to a leftward shift in the demand curve for laptops. Essentially, as the law of demand dictates, as the price of tablets decreases, the quantity demanded increases. This increase in tablet sales signifies that fewer people need to purchase laptops as they have already satisfied their computing needs with tablets. This phenomenon can be shown graphically as a leftward shift in the demand curve for laptops.