how do i find the value?

Question

Answer 1

-2(10-64) + 0 -2(64-10)

= 108 -108

= 0

which means the columns are linearly dependent

the 1st and 3rd columns are identical: -2,8,1

once you notice that, then no calculation is needed

it means det = 0

Answer 2

To find the determinant of the given 3x3 matrix:

-2((10*1)-(8*8)) - 0((8*1)-(8*1)) + -2((8*8)-(10*1)) = 0

Here is a link that you might find useful:

https://media.geeksforgeeks.org/wp-content/uploads/20220822110402/3x3.png