(2(4*x-8)+3*x)-(11*x+1-9)
(2*(4*x-8)+3*x)-(11*x+1-9)

##</code><code>##

(2*(4*x-8)):
push 2
push 4
push x
op *; (4*x) is now last on stack
push 8
op -; now 4*x-8 is last on stack
op * ; now result is last thing on stack

##</code><code>##

 2(4x-8)+3x=11x+1-9