It is not factorable. Factors of 21 are. 21 and 1
7 and 3. None of those add up to 12
Answer:
g(f(x)) = -x - 18
Step-by-step explanation:
2x - 6( (x + 6) / (2) )
2x - 3( x + 6)
2x - 3x - 18
-x - 18
1/3(x)=22-x
x/3=22-x
(x/3=22-x)3
3x=66-3x
6x=66
x=11

This should be the answer. Hope this helps! The three next terms are 25, 31, 37.