X and Y are complementary goods

X and Y are complementary goods. Explain the sequence of effects of a fall in the price of X on the equilibrium price and quantity of Y.

In case of complementar y goods, when the price of X falls, demand for commodity
Y increases.
As a result, demand curve of commodity
Y will shift towards right but supply curve remains constant. Due to increase in demand of commodity Y, there will be excess demand. Therefore, supplier will be motivated to increase the price of commodity Y. The equilibrium price and quantity would tend to increase.