2. A and E.
6. matrix row 1: 2, -3, 0; row 2: 1, 8, -7; row 3: -11, 4,
5.
10a. matrix A.
10b. matrix A.
10c. The same answer, matrix A.
10d. matrix X.
10e. matrix X.
10f. The same answer, matrix X.
14a. 2 by 3.
14b. matrix row 1: -2, 7; row 2: 7, 2.
14c. matrix row 1: -2, 7; row 2: 7, 2. Note A + B = B + A.
18a. matrix row 1: 1, -1; row 2: -1, 1. Note interchange rows
for columns.
18b. matrix row 1: -4, -4, -4; row 2: 4, 4, 4.
18c. matrix K.
22. AB = [17], a 1 by 1 matrix; BA is a 3 by 3 matrix with
row 1: 18, 0, -36; row 2: -10, 0, 20; row 3: 1/2, 0, -1.
26. AX=B. matrix A row 1: 3, 2, -4; row 2: -2, -3, 7; row
3: 5, 2, -9; matrix X column 1: x, y, z; matrix B column 1: 1,
8, 10.
30a. matrix row 1: -1, 5, 2; row 2: -1, 3, 1; row 3: 1/2,
-1, -1/2.
30b. No inverse matrix exists.
30c. matrix row 1: 1, -2, 3, 8; row 2: 0, 1, -3, 1; row 3:
0, 0, 1, -2; row 4: 0, 0, 0, -1.
34. x = 3, y = -3, z = -2.
