SOLUTION: 7(log81 9)(log2 80 - log2 5) I am having trouble with the steps to answer how to evaluate this logarithmic expression. I know that log 2 can be combined to log2 80/5 but I'm los

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: 7(log81 9)(log2 80 - log2 5) I am having trouble with the steps to answer how to evaluate this logarithmic expression. I know that log 2 can be combined to log2 80/5 but I'm los      Log On


   

Question 930369: 7(log81 9)(log2 80 - log2 5)
I am having trouble with the steps to answer how to evaluate this logarithmic expression. I know that log 2 can be combined to log2 80/5 but I'm lost after that.
Found 2 solutions by MathLover1, MathTherapy:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
if you have this:
7%28log%2881%2C+9%29%29%28log%282%2C+80%29+-+log%282%2C+5%29%29, then

7%28log%2881%2C+9%29%29%28log%282%2C+80%2F5%29%29.......log%2881%2C+9%29=log%289%2C9%5E%281%2F2%29%29

7%28log%289%2C9%5E%281%2F2%29%29%29%28log%282%2C+80%2F5%29%29

7%281%2F2%29%28log%289%2C9%29%29%28log%282%2C+80%2F5%29%29............log%289%2C9%29=1

%287%2F2%29%28log%282%2C+80%2F5%29%29

log%282%2C+%2880%2F5%29%5E%287%2F2%29%29

log%282%2C+sqrt%28%2880%2F5%29%5E7%29%29

log%282%2C+16384%29=> equal 14

Answer by MathTherapy(10553) About Me  (Show Source):
You can put this solution on YOUR website!

7(log81 9)(log2 80 - log2 5)
I am having trouble with the steps to answer how to evaluate this logarithmic expression. I know that log 2 can be combined to log2 80/5 but I'm lost after that.


7%28log+%2881%2C+9%29%29%28log+%282%2C+80%29+-+log+%282%2C+5%29%29

7%28log+%2881%2C+9%29%29%28log+%282%2C+80%2F5%29%29

7%28log+%2881%2C+9%29%29%28log+%282%2C+16%29%29

Since 81%5E%281%2F2%29+=+9, and 2%5E4+=+16, then:

7%28log+%2881%2C+9%29%29%28log+%282%2C+16%29%29 becomes: 7%281%2F2%29%284%29, or highlight_green%2814%29