7. (10 pts) Solve the system of equations using matrix elementary row operations. You must simplify the matrix to row echelon or reduced row echelon form and must indicate your row operations using proper notation. Ay - 3(x + 52) = -44 I- y = 13 -4z 27 = = - 3y + 14z 8. (5 pts each) Given the following matrices perform the indicated operations: 1 = B= 'S 1 (a) Is the following a true statement? You must show all your work. 12 = 34 + 2B (b) Solve for the matrix X in the matrix equation 4X + 3B = 21 9. (8 pts) A= " a ,B - 3 3 and C = 12 Determine whether the following is truc; A(B - C) = AB - AC