For 19 it is number 2 that does not have x = 20.
for 20 its the last one that the variable does not equal 12.
the answer for 21 is 6.
and the answer for 22 is 72.
Answer: KJ becuase it is the first two like on but put backwards.
Use excel to draw the graph and add the trend, formula
If My math is right I think that the correct answer is C.