Explanation:
The answer is OPTION C
Find the Inverse of a 3x3 Matrix.
First
Find the Determinant of A(The coefficients of e
Proceed towards finding the CO FACTOR of the 3x3 Matrix.
+. - +
A= [ 1 -1 -1 ]
[ -1 2 3 ]
[ 1 1 4 ]
The determinant of this is 1.
Find the co factor
| 2 3 | |-1 3 | |-1 2 |
| 1. 4. | |1 4 | |1. 1 |
|-1. -1 | |1 -1 | |1 -1
| 1. 4 | |1. 4| |1 1|
|-1. -1 | |1 -1 | |1. -1
|2. 3| |-1. 3| |-1 2|
After Evaluating The Determinant of each 2x 2 Matrix
You'll have
[ 5 7 -3]
[3 5 -2 ]
[-1 -2 1]
Reflect this along the diagonal( Keep 5,5 -2)
Then switching positions of other value
No need of Multiplying by the determinant because its value is 1 from calculation.
After this
Our Inverse Matrix Would be
[ 5 3 -1 ]
[7 5 -2 ]
[ -3 -2 1]
THIS IS OUR INVERSE.
SO
OPTION C