Final answer:
A leftward shift in the supply curve leads to a greater increase in equilibrium price than a rightward supply shift, a leftward demand shift, or a simple decrease in the product's price.
Step-by-step explanation:
A leftward shift in the supply curve of product X will increase equilibrium price to a greater extent than a rightward shift in the supply curve of product X. This is because a leftward shift indicates a decrease in supply which, given stable demand, leads to higher prices. On the other hand, a rightward shift in the supply curve indicates an increase in supply which typically leads to lower prices.
A leftward shift in the demand curve of product X would result in a decrease in both equilibrium price and quantity, which is a different outcome compared to the initial scenario. A rightward shift in the demand curve would increase both price and quantity, also differing from a supply decrease. Lastly, a decrease in the price of product X doesn't directly compare because it is a result of changes in the market, not an initiator of change like shifts in demand or supply.