Please help me understand how to do these questions. I am stuck. I'm not even sure I understand what the questions are asking.

(5.5) In Exercises 39-40, a. Write each linear system as a matrix equation in the form AX = B. b. Solve the system using the inverse that is given for the coefficient matrix. The inverse of x + y + 2z = 7 2 -2 N 39. y + 3z = -2 0 3 is 9 3 3x - 2z = 0 3 The inverse of - y + 2z = 12 -1 2 2 -1 ON 40. y - z=-5 0 -1 is -1 + 2z = 10 0 2 -1