Answer Happy

Need help with the following 2 questions.
Question 1 I'm simply relatively new to matrices in general, and
Question 4 I just have no idea.
Thank you for your help.
1. = = Consider a simple model in which two commodities, i = 1,2, are related to each other. The following equations define the corresponding demand/supply functions: Qd = do + a1P1 + a2Pz; Q{ = bo + b P1 + b2P2 Q2 = do + ay P1 + a2Pz; Q3 = Bo + B1 P2 + B2P2 where Qi defines quantity demanded for commodity i, Qi quantity supplied, Pi its price, and the remaining coefficients define exogenously given parameters. Assuming that both markets clear, i.e., general market equilibrium, then: = = 9 (a) By eliminating quantities using the market clearing condition that excess demand is equal to zero, i.e., Ed = Qd - Qf = 0 and EQ = QA - Q2 = 0, express the system of the remaining equations in matrix form and define each matrix. (4 marks) (b) Describe the condition(s) needed in order for this system to have a unique non-trivial solution. (2 marks)
4. Let the following Cobb Douglas production function with constant returns to scale: Y = F(K,L) = Ka L1-a, where Y defines output, K capital, L labour, and a € (0,1). Prove that the (partial) elasticity of output with respect to capital is equal to a and that the (partial) elasticity of output with respect to labour is equal to 1 - a. (5 marks)