Let a be as above, consider ax = b where b = (31, 2, 21, 11). find x1 using cramer’s rule. (you may use matlab/octave to compute the determinants, but write out what you are
matrix a= 8 6 -3 20
4 2 -5 -7
8 2 7 20
4 2 -11 -4

x1= 1

Step-by-step explanation:

The Cramer's rule say that x1= where A1 is the matrix A change the column 1 by the vector b.

Then A1= .

Using Octave we have that  det(A1)=-3840 and det(A)=-3840.

Then x1=.

it should be a and d. lmk if i'm wrong xd