2. Assuming a competitive market in the U.S., together with a supply function: \( q{s} = 400p - 400 \) and a demand function: \( q{d} = 2400 - 400p \). When the equilibrium price and quantity are reached, what are equilibrium price and quantity? (10%). Now due to Trump's reciprocal tariff policy, the authorities impose a $4 per-unit tax to be collected from sellers. We denote \( P{c} \) as the price paid by consumers after imposed tax and \( P{s} \) as the price received by producers after tax. Please solve the after-tax equilibrium quantity (\( q^{} \)) and equilibrium prices for both consumers \( P{c}^{} \) and sellers \( P{s}^{*} \). (15%)