There's 2 web links on the subject where as:

#1: One equation uses the density of the fluid (times gravity)

(

#2: and the other equation doesnt use the density

(

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So I do not understand why both equations are not the same to calculate the travel distance of the fulid since both are related to the total distance travel after opposite ends of a fluid have pressure applied on them.... Can anyone clarify what's my mistake?

In the Web links: the Height ( h ) of part #1 should equal d1 + d2 of part#2 shouldn't it ?

#1 says P1 = density *** h *** g + P2 (or F1/A1 = density *** h *** g + F2/A2)

but #2 says Work1 = Work2 thus F1***D1 = F2***D2 (no density of the fluid is used to determine the heights D1 and D2 (D1 + D2 = h)???