SOLUTION:

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION:       Log On


   

Question 950204:
Found 2 solutions by MathLover1, MathTherapy:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

log%284%2C%28x%2B3%29%29%2Blog%284%2C%28x-3%29%29=2...change to base 10
log%28%28x%2B3%29%29%2Flog%284%29%2Blog%28%28x-3%29%29%2Flog%284%29=2
%28log%28%28x%2B3%29%29%2Blog%28%28x-3%29%29%29%2Flog%284%29=2
log%28%28x%2B3%29%28x-3%29%29%2Flog%284%29=2
log%28x%5E2-9%29=2log%284%29
log%28x%5E2-9%29=log%284%5E2%29
log%28x%5E2-9%29=log%2816%29....if log same, then
x%5E2-9=16
x%5E2=16%2B9
x%5E2=25
x=sqrt%2825%29
solutions:
x=5 or x=-5
our solution will be only highlight%28x=5%29
we cannot use this solution x=-5, it will be log of negative number and log of negative number is undefined+





Answer by MathTherapy(10555) About Me  (Show Source):
You can put this solution on YOUR website!
solve the logarithimic equation algebraicially
log4(x+3)+log4(x-3)=2


log+%284%2C+%28x+%2B+3%29%29+%2B+log+%284%2C+%28x+-+3%29%29+=+2

log+%284%2C+%28x+%2B+3%29%28x+-+3%29%29+=+2 

log+%284%2C+%28x%5E2++-+9%29%29+=+2 ----- Logarithmic form

x%5E2+-+9+=+4%5E2 ---------- Converting to exponential firm

x%5E2+-+9+=+16

x%5E2+=+16+%2B+9

x%5E2+=+25

highlight_green%28x+=+5%29             OR              highlight_green%28-+5%29 (ignore)