Shoes and socks both are complementary to each other and are used together. Therefore, the increase in shoe price will discourage the demand for socks. Therefore, due to the decrease in demand for socks, the demand curve for socks will shift leftwards parallelly from D1D1 to D2D2. The supply remaining unchanged, at the equilibrium price Pe,there exists excess supply of socks, which reduces the price of socks and the new equilibrium will be at E2, with equilibrium price P2 and equilibrium quantity q2.
Price decreases from P1 to P2
Demand decreases from qe to q2
equilibrium point shifts from E1 to E2.