Hi,

You can differentiate the first row (or column) and keep the entries of other row untouched. You'll get a new determinant. Then differentiate the second row of the original determinant and keep the other row entities as it is. Similarly do this for the third row. At the end you'll get 3 new determinants. Find the sum of all three together, the resultant determinant will be your answer.

For example: https://www.qc.edu.hk/math/Advanced%20Level/Diff_determinant.htm

Hope you got the point .....

Good Luck!