I offer the following solution from somewhat flimsy reasoning!
x and y replace the question marks.
Observe: 17+39+21=37+39+1.
Subtract each cell from the value in the central cell:
39-x |
11 |
38 |
22 |
0 |
18 |
2 |
30 |
39-y |
Observe: 2(30-11)=38.
Rotate the table. Apply the observation: (22-18)(39-y)=39-x, so 117=4y-x.
22+18=38+2=40; apply this to the rotated table: 39-x+39-y=40, 38=x+y so x=38-y.
117=4y-38+y, 5y=155, y=31, so x=7.