Questions on Algebra: Logarithm answered by real tutors!

Tutors Answer Your Questions about logarithm (FREE)

Question 460601: Hey,
I am studying for a test and I have a problem I'm stuck on. I know the solution to the problem but I'm not sure how to get there.
Here's the problem:
"How many years would it take an amount of oney to triple if it is invested at a rate of 5% compounded continuously?"
To me that translates to A=Pe to the rt, so 3=e to the 0.05t, so ln 3=0.05t. THE SOLUTION is 20 ln 3. How does one get from ln 3 = 0.05t to 20 ln 3 = t?
I hope I explained that clearly. Thanks for your help!
Jessica
Click here to see answer by lwsshak3(6505)

Question 460613: f(.8)= 2 log (x)
Click here to see answer by edjones(7569)

Question 460653: simplify log base 2 of 8 - log base 2 of 4
Click here to see answer by jim_thompson5910(28595)

Question 460707: How do you factor this (3x+5)(x-2)+(2x-3)(x-2)
Click here to see answer by MathLover1(6634)

Question 460232: if log3 equals t, then log 2700 can be expressed as what?
Click here to see answer by lwsshak3(6505)

Question 458771: solve for x:
log5x + log25x=2.5
Click here to see answer by lwsshak3(6505)

Question 454172: how do i evaluate
log(base 3)1/3 + log(base 5) square root 5
Click here to see answer by lwsshak3(6505)

Question 460831: I am resubmitting this problem on logarithm, I entered yesterday, but got no response. Please help! Find f(x) such that h(x) = f∘g(x), where g(x)=8x+4, and ____ h(x)=Ö8x+4. Thank you

Click here to see answer by Edwin McCravy(8909)

Question 461053: I tried to solve this in all my calculators I have and all of them say unable to solve this type of logarithm even tho all of them have the (ln) function. Here is the equation
2ln(x-3)=ln(x+5)+ln4
When I input it in it asks if i'm solving for x or e.. not sure where the are getting the e from but anyway.. any help would be appreciated.
Click here to see answer by ankor@dixie-net.com(15652)

Question 461179: log5log5log2x=0, x=?

Click here to see answer by stanbon(57347)

Question 461479: I'm having trouble with this question... and all my calculators give me the same answer which is none of the ones available.
Solve the equation
log(2+x)-log(x-5)=log 4
answers are
A) 7/2 b 22/3 C 22/-3 D 0
Any help would be appreciated.
Click here to see answer by graphmatics(170)

Question 461481: One last one... Convert to exponential form.. again none of my calculators show the answers available.
log 0.0000001=-7
A)-7^10=0.0000001 B) 0.0000001-7=10 C 10^-7=0.0000001 D)10 0.0000001=-7
any help would be appreciated.
Click here to see answer by MathLover1(6634)

Question 461526: Which application of exponential decay do you feel is the most important? Describe, give a model, and explain why?
Click here to see answer by richard1234(5390)

Question 461820: Hey,
Quick question. I have the following problem:
Using properties of logarithms, find the exact value of the expression:

I know Change-of-Base formula, and that , but I don't know how to get to the answer, which is 18.
A little explanation of the steps would be much appreciated!
Thanks,
Jessica
Click here to see answer by asuar010(324)

Question 461926: Hello,
I have a problem that asks the following:
find
where =2, =6, and =-2
I know the answer is -5; how to get there is beyond me. A little help would be amazing!
Thanks,
Jessica
Click here to see answer by stanbon(57347)

Question 462323: solve log(2x+5)=3
Click here to see answer by math-vortex(472)

Question 462322: Evaluate the expression:
t^logt(5x^2 - 2x+7)
Click here to see answer by lwsshak3(6505)

Question 462431: Solve the equation:
log4(x)-log4(2x-3)=3
Click here to see answer by josmiceli(9680)

Question 462441: express the following as single logarithm.
log a x + log a y - log a 5
thank you.
Click here to see answer by math-vortex(472)

Question 462600: Please give step by step instructions on solving this problem...

Click here to see answer by math-vortex(472)

Question 462741: logx=log10 find x
Click here to see answer by stanbon(57347)

Question 462774: Solve for x. log5 x=.5. Express the answer to the nearest hundreth.
Click here to see answer by Gogonati(809)

Question 462919: Hello, I need help finding the vertical asymptote and the domain and range of a logarithm.
log(x+8)
I tried it myself and got (-8, infinity) for the domain and (-infinity, infinity) for the range. I also got x= -8 for the V.A.
help?
Click here to see answer by jim_thompson5910(28595)

Question 463692: log(2-x)=.05
Find X
Click here to see answer by nerdybill(6959)

Question 463878: I have a question regarding radioactive decay. I am trying to solve the following problem:
A certain amount of radioactive material decays according to the function A(t)=Ao e^-3t, where time is measured in hours. What is the half-life of the material in hours?
So I know that I'm trying to find when A(t) equals half the original amount (Ao), but I'm not sure how to solve. I know that the solution is supposed to be ln(2)/3, just wondering how to get there.
Thanks,
Jessica
Click here to see answer by stanbon(57347)

Question 463917: lorarithmic form
9^4=6561
Click here to see answer by nerdybill(6959)

Question 464240: What is the real value of x in the equation log345 - log35 = log7x?
Click here to see answer by nerdybill(6959)

Question 464260: A logarithm is an exponent. Explain, in your own words, why this is so. Justify your explanation with an example.
Thank you!
Click here to see answer by richard1234(5390)

Question 464317: Log(base 3)a*log(base a)x=5,then x=?
Click here to see answer by MathLover1(6634)

Question 464361: how to solve 9log9(4)
Click here to see answer by stanbon(57347)

Question 464366: how to solve log4(x)=2-log4(x-6)
Click here to see answer by stanbon(57347)

Question 464432: Prove that log 3=(log 2)+ (1/2)-(1/8)+(1/24)-(1/64)+....and so on.
Click here to see answer by richard1234(5390)

Question 464677: Find all real solutions (the fours after the logs are the bases of the logarithms): log4[x]+log4[x-63]=3
Click here to see answer by ewatrrr(10682)

Question 464786: please help me solve these question. logx=2log3-1/2log25+3log2-log3/5 ,find value of 'x'
Click here to see answer by stanbon(57347)

Question 464960: Loga 1.5=r Loga 5=t find loga 7.5=?
Click here to see answer by robertb(4012)

Question 465357: I have the following problem:
" Use the properties of logarithms to find the exact value of the expression:
3 log 10 - log 25 - log 4 "
I know that the answer is 1. Not sure on the properties that get us there.
Thanks,
Jessica
Click here to see answer by ewatrrr(10682)

Question 465374: I have a quick clarifying question:
I solved a problem to where the two results are e^x= 1/3 or e^x= -2. I believe that you can't deal with the -2 because it's negative, but then my answer key is telling me that x= -ln 3. I guess this is because ln 1/3 is ln 1 - ln 3, but wouldn't that be -ln 2. I hope that makes sense to you, because I am confused. I guess I just need a little brush-up on some properties here.
Thanks,
Jessica
Click here to see answer by richard1234(5390)

Question 465437: Using the tables in the reference section, find the common logarithm of the number. Type the logarithm in mantissa + characteristic form.
log 42.7 = ? + ?
Click here to see answer by Edwin McCravy(8909)

Question 465502: I need to solve the following:
-=2
*I had to write this differently because of the formula plotting system (the second part is really e to the -x instead of 1/e^x).
So I believe from here you subtract 2 from both sides and end up with everything equal to zero, and then you would let u=, so that you have u-(1/u)-2=0. Then I get confused as to how to solve this by using the quadratic formula, because I don't know what b=? . That is really all I am confused on, assuming I'm going about this the right way in the first place.
I hope I've explained that well. Thanks!
Jessica
Click here to see answer by Alan3354(30993)

Question 465529: please help me ive been staring st these questions for hours.
Express as a single logarithm
log 64 = x log 2
and also
10(r+1) = 2
Click here to see answer by richard1234(5390)

Question 465532: log2x+1/2log2(x+2)=2
solve for x
Click here to see answer by lwsshak3(6505)

Question 465828: I need help with this as I cannot figure this out:
Write the expression as the logarithm of a single number or expression with a coefficient of 1 assume all variables represent positive numbers.
log5+log10-log2
A)log 9 B)log 4 c) log 25 d log 3
any help would be appreciated.

Click here to see answer by kingme18(98)

Question 465559: Given that logcx = a and logcy = b:
Find in terms of a and b:
a) logc(c^2 x^4 y^3)
b) logc((c^3 x^2)/5rooty)
c) logy(x^2)

Click here to see answer by lwsshak3(6505)

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