The four numbers ABCD are arranged in two rows and two columns, and a vertical line is added on both sides to mark ABCD, and ABCD = ad BC is defined If x + 1 1-x 1-x + 1 = 8, then x

The four numbers ABCD are arranged in two rows and two columns, and a vertical line is added on both sides to mark ABCD, and ABCD = ad BC is defined If x + 1 1-x 1-x + 1 = 8, then x

By definition, left = (x + 1) (x + 1) - (1-x) (1-x) = 8,
So it is reduced to 4x = 8,
The solution is x = 2