Help please, solve for X - simple algebra

What order do you want?

Try
let r = (1/P)-1          (not 1/(P-1)

F = (X^r)/Y^r) - 1

F = ( (X/Y)^(1/P-1) ) -1
F+1 = (X/Y)^(1/P-1)
(F+1)^-(1/P-1) = (X/Y)
Y*(F+1)^-(1/P-1) = X

ozo, your equation doesn't seem to work when I put in real numbers.  I get 18.43 on your formula but was expecting 34.

F = 2.4
X = 34
Y = 10
P = 2

2.4    = ((34/10)^(1/(2-1))-1)

10*(2.4+1)^-(1/2-1) = 18.43

when you plug in
X = 34
Y = 10
P = 2
( (34/10)^(1/2-1) ) -1 = -0.4576738554533 != 34

((34/10)^(1/(2-1))-1)
is different from ( (X/Y)^(1/P-1) ) -1)

I get 2.4 when I cut and paste the following into Excel :  ((34/10)^(1/(2-1))-1)

But this formula works great!   Y*(F+1)^(P-1)/1 = X

For proof, I get 34 in Excel when I plug in the numbers: 10*(2.4+1)^(2-1)/1

Awesome, thanks so much!!!!!!!!!!!!!!!

Note to self:

This is the reverse CAGR formula http://www.igetit.net/newsletters/Y06_08/CalculateGrowth.aspx

F = 2.4 (CAGR, in percent, annualized)
X = 34  (Ending dollar amount)
Y = 10 (starting dollar amount)
P = 2 (period [in years])