Questions on Algebra: Logarithm answered by real tutors!

Tutors Answer Your Questions about logarithm (FREE)

Question 114805: Solve the following:
log(z^2-25)-log(z+5)=log7
Click here to see answer by solver91311(16868)

Question 115288: 3^x=6^(x+1)
Click here to see answer by stanbon(57214)

Question 115302: If log3(x+1)-log3(x-1)=2, then x=A/8 where A=
Click here to see answer by stanbon(57214)

Question 115289: If e^(2x)-9e^(x)+18=0 , then the solutions (arranged in increasing order of x) are x=_______and x=________

Click here to see answer by ganesh(20)

Question 115400: Agh...I am having major trouble understanding Logs!
Please help??
1. log x =3 (answers: a.30, b.300, c.1000, d.3000)
2. 9^x=11 (answers: a. 1.0192, b. 1.0913 , c. 1.1314 , d. 1.1163)
thanks for any help!
Click here to see answer by bucky(2189)

Question 115401: Am trying to answer homework questions, and I cant seem to get these log questions right, please help???
1. if log(a)2= .301 , log(a)6= .778 , log(a)7= .845 then what is log(a)42?
(a. .067, b. .065741, c.1.079 , d.,1.623) I am leaning towards 1.623, but I am not 100% sure.

Click here to see answer by ankor@dixie-net.com(15622)

Question 115300: A small lake is stocked with a certain species of fish. The fish population is modeled by the function
P=10/1+4e^-0.8t
where, P is the number of fish in thousands and t is measured in years since the lake was stocked.
The fish population (correct up to two decimal places) after 3 years is______
(Remark: don't forget to use the correct units for P .)
The fish population reaches 5000 after years is __________ (correct up to two decimal places).

Click here to see answer by ankor@dixie-net.com(15622)

Question 115571: i really don't know where to begin with this problem at all?
given log base a 2= 0.431 and log base a 3= 0.683 find the following ....
log base a 6 and log base a 81 and log base a 2a?

if you could help me it would be great thank you !
Click here to see answer by bucky(2189)

Question 115648: Hi!
I need help with log(x+6)- logx= log(x+2)
Thanks so much
Click here to see answer by vertciel(183)

Question 115690: I understand logarithms mostly but I can't remember how to do logarithms with a base other than 10 in my calculator. Please tell me how to put it in my calculator.
Click here to see answer by jim_thompson5910(28476)

Question 115756: Solve for x: x= radical 2x-7+5
I have worked the problem
(x-5)^2 =2x-7
x=8 and x=4
But I don't know how to do the check, can you help?
Click here to see answer by jim_thompson5910(28476)

Question 115772: Simplify: log5radical 0.1
I think it's -.2 but I don't know how to work the problem
thank you
Click here to see answer by stanbon(57214)

Question 115776: hi i need help with these three problems
a) x^3e^x-4xe^x=0

b)e^1-5x= 3 square root of e
c) (lnx)^4= 4lnx
Click here to see answer by stanbon(57214)

Question 115796: log8(x+6)-log8x=2
Click here to see answer by edjones(7569)

Question 115755: Simplify: .

Click here to see answer by Nihat Routsong(11)

Question 115904: okay i need help with this one:
49^x = 7^(x^2)-15

thanks!
Click here to see answer by josmiceli(9645)

Question 115924: write as a logarithm of one quantity:2log4(X) +log4(X)-log4(3x-2)
Click here to see answer by josmiceli(9645)

Question 116158: 1. log(3)x=-2
(answers: -8, -6, 1/9, 9)
2. 7^x=8
(answers:.06, .94, .98, 1.07)

Click here to see answer by jim_thompson5910(28476)

Question 116270: Bear with me I'm not sure how to enter certain symbols:( Sorry.)
Expand as much as possible and evaluate:
log3(base) then radicand symbol (index is 4) and x^5 y^4/81 is inside the
radicand symbol.
I noticed the two equations inside the radicand symbol were divided so I
know this means I have to write it as subtraction.
log3(x^5y^4)^1/4-log3 (81)1/4
log3 (x^5/4 y^4/4) - 1/4 log3 (81)?
5/4 log3 X + 4/4 log3 Y - 9/4?
Please help our study group was coming up with 3 different answers and I'm not
sure any of us were sure what to do.:)
Click here to see answer by psbhowmick(529)

Question 116316: Suppose that the number of cars, C, on 1st Avenue in a city over a period of time t, in months, is graphed on a rectangular coordinate system where time is on the horizontal axis. Suppose that the number of cars driven on 1st Aveue can be modeled by an exponential function, C=p*a^t where p is the number of cars on the road on the first day recorded. If you commuted to work each day along 1st Avenue, would you prefer that the value of t be between 0 and 1 or larger than 1? Explain your reasoning.
Click here to see answer by stanbon(57214)

Question 116440: Please help me solve this equation:
Click here to see answer by checkley71(8403)

Question 116572: Suppose that the function P=12 +50 ln x represents the percentage of inbound e-mail in the US that is considered spam, where x is the number of years after 2001.
Use this model to approximate the year that the percent of spam will reach 90% provided that law enforcement regarding spammers does not change.
Click here to see answer by Fombitz(13828)

Question 116577: Suppose that the funtion P=12+50ln x represents the percentage of inbound e-mail in the US that is considered spam, where x represents the number of years after 2001.
Use this model to approximate the year that the percentage of spam will reach 90% provided that law enforcement regarding spammers does not change.
Click here to see answer by stanbon(57214)

Question 116576: Describe the transformation on the following graph of f(x) = log(x). State the placement of the horizontal asymptote and x-intercept after the transformation. For example, "left 1" or "stretched vertically by a factor of 2" are descriptions.
a) g(x) = log(x+2)
b) g(x) = -log(x)
Click here to see answer by stanbon(57214)

Question 116575: Describe the transformation on the following graph of f(x) = e^x. State the placement of the horizontal asymptote and y-intercept after the transformation. For example, "left 1" or "rotated about the y-axis" are descriptions.
a) g(x) = e^x + 3
b) h(x) = e^-x
Click here to see answer by stanbon(57214)

Question 116597: Solve for x:

Click here to see answer by jim_thompson5910(28476)

Question 116946: Brad invested $2,400 in a three year CD that pays four percent componded annually. What is the compound interest and amount that will be in the bank after three years?
Click here to see answer by stanbon(57214)

Question 117056: Suppose that 2000.00 is invested at the rate of 6% per year compounded continuosly. What is the balance after 1year ? after 2years?
Click here to see answer by checkley71(8403)

Question 117037: Can you please help me solve for "x"
I got as far as (2x-9)/(5x-2)=1
Thank You for your help.
Click here to see answer by scott8148(6628)

Question 117057: A computer is infected with a virus, assume that it infects 20 other computers within 5 minutes, and that these pc's and servers each infect 20 more machines within another 5minutes, etc. How long until 100million computers are infected
Click here to see answer by edjones(7569)

Question 117059: Suppose that 2000.00 is invested at a rate of 6% per year compounded continuously. What is the balance after 1 year? After 2 years
Click here to see answer by bucky(2189)

Question 117637: i was wondering how to solve log 3x=1
Click here to see answer by jim_thompson5910(28476)

Question 117717: Is there someone that can help me with this problem? I've done these before but have since forgotten.
log sqrt(x^3-9)=2
Do I need to add the 9 and leave Log sqrt(x^3) =11?
Click here to see answer by jim_thompson5910(28476)

Question 117795: I am trying to review for a final and would like to get help with A &B:
a. y= (10^x-10^-x)/ (2)
b. y= (e^x +e^-x) / (2)
Click here to see answer by stanbon(57214)

Question 117795: I am trying to review for a final and would like to get help with A &B:
a. y= (10^x-10^-x)/ (2)
b. y= (e^x +e^-x) / (2)
Click here to see answer by checkley71(8403)

Question 117944: I am studying for my final and was wondering if I could get help with this problem: Solve the compound interest formula for t by using natural logarithms. A=P(1+r/n)^nt
Click here to see answer by Earlsdon(6287)

Question 117972: This word problem is very confusing, help me find out the answer:
A certain radioactive isotope has a half-life of approximately 1900 years. How many years to the nearest year would be required for a given amount of this isotope to decay to 80% of that amount.
A. 612 years
B. 380 years
C. 532 years
D. 4412 years
I have tried: . Nothing seems to work. Also I know I have to round and use a T.I. and I did, but my answer doesn't come close to the answer choices.
Click here to see answer by ankor@dixie-net.com(15622)

Question 117116: =
Click here to see answer by Edwin McCravy(8879)

Question 118205: log y=log(a*e^x)
Click here to see answer by wgunther(43)

Question 118623: log(base 10)y + log(base 10)(y+3)=1
Click here to see answer by stanbon(57214)

Question 118628: 6^x>42
Click here to see answer by stanbon(57214)

Question 118699: log5+logx=2
Click here to see answer by ankor@dixie-net.com(15622)

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