First see following example

1 2 3 । A । = 4 5 6 7 8 9

Above is determinant and we can calculate its value by expending it

If we calculate co-factors of first row and then multiply with respective element and then sum of these . After this what we found will be the value of determinant .

You should also know co-factor

What is co- factor ?

If we multiply - 1's power m + n with minor , then what we obtain will be co -factor .

You should also know minor

What is minor

Minor is submatrix , if we leave selected element's row and column

for example

`------1 2 3 । A । = 4 5 6 7 8 9`

`------------- 5 6 1's minor is = 8 9`

1' co-factor = - 1's power ( 1+1 because it is first row and first column element ) and

```
multiply with 5 6
--------------- 8 9
```

Now , you will able to calculate the value of determinant

। A । = 1 X 5 6 - 2 X 4 6 + 3 X 4 5 8 9 7 9 7 8। A । = 1 X ( 9 x 5 - 6 X 8 ) - 2 ( 9 X 4 - 7 X 6 ) + 3 X ( 8 X 4 - 7 X 5 )

। A । = -3 + 12 -9 = 0

So , value of determinant is Zero