SOLUTION: {{{ log (21, (x+84) ) = 3-log (21,x) }}}

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: {{{ log (21, (x+84) ) = 3-log (21,x) }}}      Log On


   

Question 881262: +log+%2821%2C+%28x%2B84%29+%29+=+3-log+%2821%2Cx%29+
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Solve for x:
+log+%2821%2C+%28x%2B84%29+%29+=+3-log+%2821%2Cx%29+
+log+%2821%2C+%28x%2B84%29+%29%2Blog+%2821%2Cx%29+=+3+
+log+%2821%2C+%28x%2B84%29%28x%29%29+=+3+
21^3=x^2+84x
x^2+84x-9261=0
(x+147)(x-63)=0
x=-147 (reject, (x+84)>0)
or
x=63