College Algebra, 2013a

596 Systems of Equations and Matrices
⎡
5. For A = ⎣
7
8
9
⎡
ˆ 3A = ⎣
⎤
⎦ and B = [ 1 2 3 ]
21
24
27
⎤
ˆ A 2 is not defined
⎡
ˆ AB = ⎣
⎡
6. For A = ⎣
ˆ 3A = ⎣
⎦ ˆ −B = [ −1 −2 −3 ]
7 14 21
8 16 24
9 18 27
1 −2
−3 4
5 −6
⎡
3 −6
−9 12
15 −18
⎤
ˆ A − 2B is not defined
⎦ ˆ BA = [50]
⎤
⎦ and B = [ −5 1 8 ]
⎤
⎦ ˆ −B = [ 5 −1 −8 ]
ˆ A 2 is not defined
ˆ A − 2B is not defined
ˆ AB is not defined ˆ BA = [ 32 −34 ]
⎡
7. For A = ⎣
ˆ 3A = ⎣
2 −3 5
3 1 −2
−7 1 −1
⎡
⎡
ˆ A 2 = ⎣
⎡
ˆ AB = ⎣
⎤
6 −9 15
9 3 −6
−21 3 −3
⎡
⎦ and B = ⎣
⎤
−40 −4 11
23 −10 15
−4 21 −36
1 0 0
0 1 0
0 0 1
[ ] −4 −29
8. 7B − 4A =
−47 −2
⎤
1 2 1
17 33 19
10 19 11
⎦ ˆ −B = ⎣
⎤
⎦ ˆ A − 2B = ⎣
⎦ ˆ BA = ⎣
⎤
⎦
⎡
⎡
−1 −2 −1
−17 −33 −19
−10 −19 −11
⎡
⎤
⎦
0 −7 3
−31 −65 −40
−27 −37 −23
1 0 0
0 1 0
0 0 1
[ ] −10 1
9. AB =
−20 −1
⎤
⎦
⎤
⎦