You only give two numbers so what do you mean by "the eighth term"? The eighth term of what
This has got to be one of the most silly/confusing problem I've seen
Answer is x=6; 2 series exist:
27,25,23,21,19,17,15,13 : x = -1,0,1,2,3,4,5,6
-1,1,3,5,7,9,11,13 : x = 13,12,11,10,9,8,7,6
Each term = 25-2x