SOLUTION: solve for x: log4 x- log4 (x+15)=-1

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: solve for x: log4 x- log4 (x+15)=-1      Log On


   

Question 409004: solve for x: log4 x- log4 (x+15)=-1
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
log%284%2Cx%29+-+log%284%2C%28x%2B15%29%29+=+-1
log%284%2Cx%2F%28x%2B15%29%29+=+-1
x%2F%28x%2B15%29+=+4%5E%28-1%29
x%2F%28x%2B15%29+=+1%2F4
cross-multiplying:
4x+=+x%2B15
3x+=+15
x+=+5