Hello,
Let a the first, b the second and c the third.
a+b+c=53
b=a/3
c=2a
==>a+a/3+2a=53
==>10a/3=53
==>a=15.9
c=2*a=2*15.9=31.8
b=a/3=15.9/3=5.3
Proof: a+b+c=15.9+5.3+31.8=53
The second number is 5.3
This is a proportion, she is walking 3.3 every hour. She walked for 5.4 hours. And we don't know how far she walked so its x/.54. Then you cross multiply which gives you 3.9×.54=x. We multiply those decimals and we get 1.782.
The sum (addition) of -2 and 3 times (3 ·) a number (n)
-2 + 3n
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 