Exercise 2 System of equations Consider a system of equations that represents supply and demand: = 20-4p Please write the system in the form: q = 4+4p. A a[;] = b. ■ What is the matrix A? What is the vector b? ■ What are p and q? Exercise 1 Reading a matrix Consider the matrix A, where 1 2 8 A = 7 256 1 1 Please answer the following: (50 points) What are dimensions of A? (50 points) What is the entry a12?