7.1 Re-write the following systems of equations in linear algebraic form. cty a. 3x - Ay = C. Ay + z = r+z = X- 2 b. Ax + 6y - 2x = 23 2x - 3y + 2 = d. -1 7.2 Consider the right-hand side vector b = [2, -1, 1]. Use the various A matrices below to re-write the equation Ax = b in traditional algebraic form: a. C. (0 0 09 5 8 2 OH b. 09 00 - d. 7.3 For which systems of equation in Exercise 7.1 can a unique solution be found? For which is this not possible? How do you know