In this table, each row across follows the same pattern of numbers. See if you can discern the pattern and fill in the missing number in the bottom row.

7 4 8
3 9 7
6 5 10
? 8 4

(7×4)-8 = 20
(3×9)-7 = 20
(6×5)-10= 20
(3×8)-4 = 20
The answer is 3.