Then, according to the first line, only fill in 5+8 or 6+7 to get the first column, which is impossible. So there is something wrong with the original question.

However, if you add the operation process of bracket change (multiplication and division before addition and subtraction), it can be realized.

5+8-9=4

+ - -

7-6x4 =4

÷ x -

3+2- 1=4

= = =

4 4 4

The formula is:

Row: 5+8-9=4，(7-6)x4=4，3+2- 1=4。

Column: (5+7)÷3=4, (8-6)x2=4, 9-4- 1=4.