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:
so the problem is saying 42x-10.36 so it's just saying take 10.36 away from 42 multiplied by X
Step-by-step explanation:
Answer:
-x²+9x+4
Step-by-step explanation:
Hope this helps!