SOLUTION: Solve: log y-1 = -log(y-9)

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: Solve: log y-1 = -log(y-9)      Log On


   

Question 956227: Solve: log y-1 = -log(y-9)
Answer by LinnW(1048) About Me  (Show Source):
You can put this solution on YOUR website!
log(y-1) = - log(y-9)
log(y-1) = -1* log(y-9)
log%28y-1%29+=+log%28%28y-9%29%29%5E-1
log%28y-1%29+=+log%281%2F%28y-9%29%29
y+-+1+=+1%2F%28y-9%29
%28y+-+1%29%2F1+=+1%2F%28y-9%29
%28y+-+1%29%28y-9%29=1
y%5E2-9y-y%2B9=1
y%5E2-10y%2B9=1
y%5E2-10y%2B8=0
y+=+5+%2B+sqrt%2817%29
Notice that y+=+5+-+sqrt%2817%29
will not work since this would make the value of y-9 in log(y-9) negative.