Assuming this pattern continues on, we have an arithmetic sequence with
a = 11 = first term
d = -9 = common difference
The nth term can be found like so
Let's check the answer by trying n = 3
This shows the third term is -7, which matches what the original sequence shows. The answer is partially confirmed. I'll let you check the other values of n. You should get 11 when trying n = 1, and you should get 2 when trying n = 2.
1 and 2 i can't answer without proper data. 3. x+2x+2x+6 = 86 5x+6 = 86 -6 -6 5x = 80 x = 16 Side one: x is 16 Side two: 2x is 2(16) = 32 Side three: 2x+6 is 38