How would I do these Matrices?

Question

1.
|1/2 14
10 -8|

2,
Let matrix A = [8 -2
4 7 ]
Let matrix B = 2A, Find b_22

Answer 1

1.
What do you want to do to it? Find the determinant?
If so
(1/2)(-8) - (14)(10)
= -4 -140
= -144

2.
2*7 = 14

Answer 2

Is this right then?
|12 -21
-2 -2/3|

answer-1/50

Answer 3

| 12 -21 |
| -2 -2/3|

12(-2/3) -(-21*-2)
= -8 - 42
= -50

Answer 4

What about this one? Correct?
|1 0
0 1|
The answer would be 1

Answer 5

Yes.