const arr: number[][] = [ [ 4, -1, 1 ], [ 4, 5, 3 ], [ -2, 0, 0 ] ]
/*
* a b c
* arr = d e f
* g h i
*
* determinant = a*(e*i - f*h) - b*(d*i-f*g) + c*(d*h - e*g)
*
*/
const determinant: number = arr[0][0] * (arr[1][1]*arr[2][2] - arr[1][2]*arr[2][1]) -
arr[0][1] * (arr[1][0]*arr[2][2] - arr[1][2]*arr[2][0]) +
arr[0][2] * (arr[1][0]*arr[2][1] - arr[1][1]*arr[2][0]);
console.log(determinant);
/*
run:
16
*/