In a competitive market the supply and demand functions of a good are given by P=QS+11 P=-SQD+27 Suppose that the government levies an excise tax, t, per unit. 3) Find an expression for the equilibrium quantity Q as function of t. b) Find t for which the govemment's tax revenue, T = tQ is maximised. '\"~~E)__- a)Q=D (Use integers or fractions for any numbers in the expression. Type an expression using t as the variable. ) b)t=D (Type an integer or a decimal.)