一、問答申論和計算題(共 15 分)

Consider a market where the demand function is $Qd = a - b \times P$ and the supply function is $Qs = k \times P$, with $P$ representing the price, and $Qd$ and $Qs$ representing the quantity demanded and supplied, respectively. The parameters $a$, $b$, and $k$ denote specific constants in the equations. If the government provides a subsidy of $1 per unit, calculate the deadweight loss. Is this loss greater, equal to, or less than the case if the government imposes an unit tax of $1 per unit? Why?