SOLUTION: Solve the equation 3log[base5]x - log[base5]4 = log[base5]16. Solve the equation 1/3log[base7]64+1/2log[base7]121=log[base7]x Find log[base3]25 given that log[base3]5 = 1.465

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: Solve the equation 3log[base5]x - log[base5]4 = log[base5]16. Solve the equation 1/3log[base7]64+1/2log[base7]121=log[base7]x Find log[base3]25 given that log[base3]5 = 1.465      Log On


   



Question 262519: Solve the equation 3log[base5]x - log[base5]4 = log[base5]16.
Solve the equation 1/3log[base7]64+1/2log[base7]121=log[base7]x
Find log[base3]25 given that log[base3]5 = 1.465

Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
we are given three separate problems. Lets take one at a time:
Problem #1:
3log%285%2Cx%29+-+log%285%2C4%29+=+log%285%2C16%29
step 1- use the power rule to bring all coefficients up as exponents. We get
log%285%2Cx%5E3%29+-+log%285%2C4%29+=+log%285%2C16%29
step 2 - using laws of logs if we see log subtraction, that means division, so we get
log%285%2Cx%5E3%2F4%29+=+log%285%2C16%29
step 3 - since both logs are base 5, we can eliminate then and set the rest equal. We get
x%5E3%2F4+=+16
step 4 - multiply by 4 to get
x%5E3+=+64
step 5 - take a cube root to get
x+=+4
--------
problem #2:
%281%2F3%29log%287%2C64%29%2B%281%2F2%29log%287%2C121%29=log%287%2Cx%29
step 1- use the power rule to bring all coefficients up as exponents. We get
log%287%2C64%5E%281%2F3%29%29%2Blog%287%2C121%5E%281%2F2%29%29=log%287%2Cx%29
step 2 - using laws of logs if we see log addition, that means multiplication
log%287%2C64%5E%281%2F3%29%2A121%5E%281%2F2%29%29+=+log%287%2Cx%29
step 3 - since both logs are base 7, we can eliminate then and set the rest equal. We get
4%2A11+=+x
So,
x+=+44
---------
problem #3:
Find
log%283%2C25%29
given that log%283%2C5%29+=+1.465
step 1 - rewrite log%283%2C25%29 as log%283%2C5%5E2%29 and using power rules of logs, bring the 2 out front to get
2log%283%2C5%29
step 2 - by substitution, we get
2*1.465 = 2.93