What causes both equilibrium price and quantity to increase?

An increase in demand, with supply remaining constant, can cause both the equilibrium price and quantity to rise. This shift often occurs due to factors such as increased consumer preferences, rising incomes, or a decrease in the price of complementary goods. Additionally, if supply decreases while demand remains constant, it can also lead to an increase in equilibrium price, but the quantity may fall in that scenario. Overall, a simultaneous increase in demand and supply can also result in higher equilibrium quantity, and the effect on price will depend on the relative magnitude of the shifts.