Questions on Algebra: Logarithm answered by real tutors!

Tutors Answer Your Questions about logarithm (FREE)

Question 257537: why does log(xy) = logx- log y (if the base is a for all).
Click here to see answer by ankor@dixie-net.com(15656)

Question 257856: Please help me solve this equation, it's about logarithms. Thank you (6^(x^2-2) = 48
Click here to see answer by edjones(7569)

Question 257904: log base 5 x=3
Click here to see answer by nerdybill(6962)

Question 258067: A sample of bismuth-210 decayed to 33% of its original mass after 8 days.
(a)Find the half-life of this element.
(b)Find the mass remaining after 12 days
Click here to see answer by richwmiller(9143)

Question 258093: A sample of bismuth-210 decayed to 33% of its original mass after 8 days.
(a)Find the half-life of this element.
(b)Find the mass remaining after 12 days
Equation:
m(t)= I*e^-rt
I=Initial mass
r=rate of decay
t= time
Since it is half-life, 1/2= e^-rt
rate= (ln 2)/ h
h= number of days to decay half of the mass
I wasn't given h and r. Working with two variables is confusing.
Click here to see answer by MRperkins(300)

Question 258141: Solve for x algebraically:
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Question 258147: How do I solve
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Question 258161: Find the exact solution(s) to the equation
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Question 258225: Simplify fully:
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Question 258258: Compress the expression into one simplified logarithm.
Click here to see answer by jsmallt9(3296)

Question 258550: log10^3
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Question 258629: In log N = log x + 2log y-3
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Question 258691: How would I solve:
ln ( x + 3 ) - ln ( x + 2 ) = 5
I know that you have to divide so I got: ln ( x+3/x+2) = 5 but I couldn't get any farther than that.
Click here to see answer by Edwin McCravy(8909)

Question 258738: what is the answer for log(2000)
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Question 258773: how would you answer a log question when it asks for the value of a letter(x) in simultaneous form????
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Question 259009: e^log e^2 9
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Question 259162: log3a=3a-25

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Question 259654: If log8 3 = 0.5283 and log8 5 = 0.7740, then what is the value of log8 45 ?
Click here to see answer by nerdybill(6962)

Question 259738: if log10x +log10y=3 then xy=
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Question 259754: 4. You have $760,000 in your bank account. The interest rate in your account is 5%. Solve for the following:
a. How much interest will you accumulate if interest is compounded annually over the next five years?
b. How much interest will you earn in your account over the next five years with continuous compounding? You can use a scientific calculator or the =Exp() function in Microsoft Excel. If you are crafty you can also find web pages that will do the calculations for you. Regardless, show your steps and your work.

Click here to see answer by richwmiller(9143)

Question 259642: 100=10 log(10^10 * x)
I need to solve for x so I divided both sides by ten to get:
10= log(10^10 * x)
What do I need to do next to solve for x?
Click here to see answer by Earlsdon(6287)

Question 259892: use natural log to solve: 9*2^z=19*11^z solve for z
Click here to see answer by ankor@dixie-net.com(15656)

Question 260017: Strontium–90 has a half-life of 29 years. How long will it take for an initial sample of 10 mg to decay to 1 mg?
Do I use the formula A= Ao(1/2)^t/h
If yes I come up with 1=10(1/2)^t/29 which ends up to be wrong.
So how do I proceed? Please HELP!!!
Click here to see answer by nerdybill(6962)

Question 260352: HElp! could you please do this (I couldn't)
Simplify: 9log(base 27)x - 4log(base 9)x
The answer is log(base3)x but I don't know how to get that! Thank you.
Click here to see answer by drk(1908)

Question 259316: Theformula t=1/c [1n A-1n(A-N)]
descibes the time t, in weeks, that it takes to achieve mastery of a portion of a task, where A is the maximum learning possible, N is the portion of the learning that is to be achieved, and c is a constant used to measure an individuals learning style.
a. Express the formula so that the expression in brackets is written as a single logarithm.
b. The formula is also used to determine how long it will take chimpanzees and apes to master a task. For example, a typical chimpanzee learning sign language can master a maximum of 65 signs. Use the form of the formula from part (a) to answer this question: How many weeks will it take a chimpanzee to master 30 signs if c for that chimp is 0.03?
Click here to see answer by jsmallt9(3296)

Question 260505: 1100/1+99e^-.3t=275
Click here to see answer by drk(1908)

Question 260509: use the properties of logarithms to write the expression as a sum, difference, and/or constant multiple of logarithms (assume all variables are positive): log(subscript8)x^4
Click here to see answer by drk(1908)

Question 260514: log(x+3)=1-logx
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Question 260516: log(3x)= log 5 + log(x-2)
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Question 260512: 10-log(5,2x-9)=9
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Question 260527: log(5+x)-log(x-2)=log 4
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Question 260519: log (4,2x+5)-log(4,x-2)=1
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Question 260536: ok last question! log(4,2x+5)-log (4,x-2) =1
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Question 249200: Evaluate the logarithmic equation for three values of x that are greater than 1, three values of x that are between 0 and 1, and at x=1. Show your work. Use the resulting ordered pairs to plot the graph; submit the graph via the Dropbox. State the equation of the line asymptotic to the graph (if any).

y = -log3.5 x (the x is an exponent of 5)

Click here to see answer by ilovemath(8)

Question 260775: what is log4 to base2 with the addition of log7 to base2 then subtract logX to base 2=1
Click here to see answer by drk(1908)

Question 260761: Find the lim as x approches e
lnx-1
______
x
Click here to see answer by drk(1908)

Question 261173: 5^(x-1)=12^x (estimate to 4 places)

Click here to see answer by jsmallt9(3296)

Question 261253: log338
Click here to see answer by Alan3354(30993)

Question 261361: logbase3 12+ logbase3 x = 3
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Question 261362: logbase10 x +logbase10 (x+21) = 2
Click here to see answer by stanbon(57361)

Question 261360: logbase9 5x = logbase9 6 + logbase9 (x-2)
Click here to see answer by Alan3354(30993)

Question 261358: logbase9 5x = logbase9 6 + logbase9 (x-2)
Click here to see answer by Alan3354(30993)

Question 261358: logbase9 5x = logbase9 6 + logbase9 (x-2)
Click here to see answer by stanbon(57361)

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