SOLUTION: Can someone please help me with this problem? . Determine the value of the unknown. . log81^(A-4) = -(1/4) . A = __?__ Thank you!

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: Can someone please help me with this problem? . Determine the value of the unknown. . log81^(A-4) = -(1/4) . A = __?__ Thank you!      Log On


   

Question 643069: Can someone please help me with this problem?
.
Determine the value of the unknown.
.
log81^(A-4) = -(1/4)
.
A = __?__
Thank you!
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
log81^(A-4) = -(1/4)
(A-4)log81=-.25
Alog81-4log81=-.25
Alog81=4log81-.25
A=(4log81-.25)/log81
using calculator
A=3.869..
check:
log81^(A-4)
=log[81^(3.869-4)]
=log[81^(-.131)]≈-.2500..