Question

Brian had 1/8 as many stickers as Brady. When Brady gave one-fourth of his stickers to Brian, he then had 9 fewer stickers than his friend. How many stickers did Brady have at first?

Answer 1

If Brian had x stickers, then Brady had 8x. 1/4 of 8x = 2x, so we are told that
8x - 2x = x + 2x - 9
6x = 3x - 9
Bzzzzt. x = -3

Maybe you meant that Brian still had 9 fewer than Brady. If so,
3x = 6x - 9
x = 3
They had 3 and 24 stickers.
check that 3+6 = 18 - 9 yes