Starting at the origin, a bug jumps randomly along a number line. Each second it jumps on unit to the right or one unit to the left (either move being equally likely). Describe all the places that the bug could be after eight seconds, and tell how likely each place is.

Then do it for 9 seconds

I know it has to do with (x+y)^8 but i dont know what x and y are.... -1 and 1?