To find the next two missing numbers in the sequence $12, 14; 11, 14; 9, 17; \_, \_$, we need to analyze the pattern.

Let's look at the two numbers in each pair separately:

1. First Numbers in Each Pair: 12, 11, 9, $\_$

   • To see a pattern, subtract each number from the previous one: $12 - 11 = 1, \quad 11 - 9 = 2$
   • The differences are increasing by 1 each time.
   • To find the next difference, add 1 to the last difference (which is 2): $2 + 1 = 3$.

   So, the next difference is 3. Subtracting 3 from the last number (9):

   $9 - 3 = 6$

   The next first number is 6.

2. Second Numbers in Each Pair: 14, 14, 17, $\_$

   • Check the differences between the second numbers: $14 - 14 = 0, \quad 17 - 14 = 3$
   • The difference here is first 0, then 3.
   • To find a pattern, it seems the numbers increase by 3 after staying the same:

   Continuing this pattern (adding 3 again): $17 + 3 = 20$

   The next second number is 20.

So, the next two missing numbers in the sequence are 6, 20.

Sequence with Missing Numbers Filled:

12, 14;