I need help with the last 2 parts of this question

A competitive market is described by the following system of equations: P=3+2QP=36Q If demand accurately represents marginal benefit and supply accurately represents marginal cost, what is the dollar value of total surplus in this market? $ Suppose instead that there is an external social benefit of consumption of $3 per unit. What would the allocatively efficient quantity be in this market? Q= With the external social benefit of $3 per unit, what is the true marginal social benefit of the market quantity that will be exchanged in the market? $ With the external social benefit of $3 per unit, what is the true marginal cost of the market quantity that will be exchanged in the market? Which of the following would be ways to achieve the socially optimal quantity in this market? Choose all that apply. Quota of 7 units Tax of $3 per unit on sellers Subsidy of $3 per unit on sellers Tax of $3 per unit on buyers Quota of 6 units Subsidy of $3 per unit on buyers A competitive market is described by the following system of equations: P=3+2QP=36Q If demand accurately represents marginal benefit and supply accurately represents marginal cost, what is the dollar value of total surplus in this market? $ Suppose instead that there is an external social benefit of consumption of $3 per unit. What would the allocatively efficient quantity be in this market? Q= With the external social benefit of $3 per unit, what is the true marginal social benefit of the market quantity that will be exchanged in the market? $ With the external social benefit of $3 per unit, what is the true marginal cost of the market quantity that will be exchanged in the market? Which of the following would be ways to achieve the socially optimal quantity in this market? Choose all that apply. Quota of 7 units Tax of $3 per unit on sellers Subsidy of $3 per unit on sellers Tax of $3 per unit on buyers Quota of 6 units Subsidy of $3 per unit on buyers