what are the rules for these two problem? I can not figure it out. I spent 30 minutes trying to figure it out

Question

1, 10
2, 9
3, 8
4, 7
lI know the left is increasing by one and the right is decreasing by one but I can't find an equation for this.

and the second one is

0, -5
1, -12
2, -17
3, -22
4, -27

I know the

Answer 1

Xn = 11 - n

Xo = -5 (I think the first one should be -7)
Xn = -7 - 5 n

Answer 2

or for the second one
Xn+1 = Xn -5
again the first one does not fit