Answer with Step-by-step explanation:
We are given that
A and B are matrix.
A.We know that for two square matrix A and B
Then, 
Therefore, it is true.
B. det A is the product of diagonal entries in A.
It is not true for all matrix.It is true for upper triangular matrix.
Hence, it is false.
C.

When is a factor of the characteristics polynomial of A then -5 is an eigenvalue of A not 5.
Hence, it is false.
D.An elementary row operation on A does not change the determinant.
It is true because when an elementary operation applied then the value of matrix A does not change.
Answer:
The inequality is 
Step-by-step explanation:
we know that
In the figure, the value of c is less than -1
so

Adds both side +2


Answer:
She bought 11 stickers
Step-by-step explanation:
20 - 12.85
7.15
then
7.15/0.65
11
First subtract 8.5 from both sides, then divide the -1.2 to get x by itself
x=1.5
Answer:
x = 2/5
Step-by-step explanation:
5x=2
Divide each side by 5
5x/5 = 2/5
x = 2/5