First, replace the elements in the third row with 1 3 -2 2 to form a new fourth-order determinant. The result of finding this determinant is the answer. When solving, you can add the third column to the fourth column first. A34 a44 are all zeros. Add the line 1 to the second line, so that a24 also becomes 0. Finally, expand according to the fourth column. The result is 24.