I can't seem to figure out what I am doing wrong

express in form a/b

0.9 (bar)

So I start...

x = 0.99999...

10x = 9.9999...

LHS:

10x - x = 9x

RHS:

9.9999 - 0.9999 = 9

so 9x = 9

thus x = 1

So now I am stuck and can't seem to figure out where I went wrong... plz help