log(x1) = log(2) = 0.30102999566399
log(x2) = log(3) = 0.47712125471967
log(x3) = log(7) = 0.84509804001426
log(x4) = log(0) = undefined, this is where the formula falls apart
note: the domain of log(x) is x > 0
A much better approach is to multiply the values out:
x1*x2*x3*x4*x5 = 2*3*7*0*(-8) = 0
Then raise that result to the (1/5) power
0^(1/5) = 0
(