Question 133254
log 11 = log(10^(z+4) + 10^(z+3))

log 11 = log(10000*10^z + 1000*10^z)

log 11 = log(11000*10^z)

log 11 = log11000 + log10^z

log 11 = log11000 + z
z = log11 - log11000

z = log(11/11000)

z = log(1/1000)

z = -3
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Cheers,
Stan H.