ANSWER
24
EXPLANATION
For a matrix A of order n×n, the cofactor
of element
is defined to be

is the minor of element
equal to the determinant of the matrix we get by taking matrix A and deleting row i and column j.
Here, we have

M₁₁ is the determinant of the matrix that is matrix A with row 1 and column 1 removed. The bold entries are the row and the column we delete.

Since the determinant of a 2×2 matrix is

it follows that

so 
Answer: 8
Step-by-step explanation:
It’s B, the number of cubic units it takes to fill a solid figure
Answer:
p = -15
Step-by-step explanation:
-2 = (p+9)/3 multiply both sides by 3 to get rid of fraction
-6 = p + 9 subtract 9 from both sides
-15 = p