Let the demand and supply functions be as follows: (a) Qd51-3P = (b) Qd: 30-2P = Q₁ = 6P - 10 Q₁ = −6+5P Qs find P* and Q* by elimination of variables. (Use fractions rather than decimals.) 3. According to (3.5), for Q* to be positive, it is necessary that the expression (ad - bc) have the same algebraic sign as (b+d). Verify that this condition is indeed satisfied in the models of Probs. 1 and 2. 4. If (b + d) = 0 in the linear market model, can an equilibrium solution be found by using (3.4) and (3.5)? Why or why not? 5. If (b + d) = 0 in the linear market model, what can you conclude regarding the posi- tions of the demand and supply curves in Fig. 3.1? What can you conclude, then, regarding the equilibrium solution?