Common voltage of 2 op amps instrumentation amplifier
Well, just set R9 to be zero, and all bridge resistors to be 120 and the potential divider produces a ratio of 360/480 and clearly that's wrong because it should be 0.5. At this point, if I were you I'd ignore the document and find another I could rely on.
Moving on... just look at the glaring error putting R5 in the numerator when they meant R9 so, if I used R9 = 0 in that formula instead of R5 then it comes up with the right answer but, I'd be tossing this document in the bin for such glaring mistakes: -