Can you tell me if these are correct? I am not sure that I understand this.

1. Which is the solution for the determinant?
|10 0)|
5 -7
Answer- -70?

2.Which is the solution for the determinant?
|1 7)|
0 -3
Answer- -3

Did I answer these correct?

19.Given matrices A, B, and C are all 2x2, determine whether the equation is true for the given matrices.
C(A+B)= CA + CB
Answer- False

20.Matrix multiplication is not commutative.
Answer-False

21.For matrices, A + B = B + A
Answer-True

To calculate the determinant of a 2x2 matrix, you can use the formula:

det(A) = (a * d) - (b * c)

In the first example, the given matrix is:
|10 0|
|5 -7|

Using the formula, we substitute the values of a, b, c, and d:
a = 10, b = 0, c = 5, d = -7

Now, we can calculate the determinant:
det(A) = (10 * -7) - (0 * 5) = -70 - 0 = -70

So, the answer to the first question is indeed -70.

In the second example, the given matrix is:
|1 7|
|0 -3|

Using the same formula, we substitute the values of a, b, c, and d:
a = 1, b = 7, c = 0, d = -3

Now, we can calculate the determinant:
det(A) = (1 * -3) - (7 * 0) = -3 - 0 = -3

So, the answer to the second question is indeed -3.