A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 4 years ago
solve the equation ln(X3)=ln(X+2)+3 how do you cancel ln. I know when you have log you can do this= log base 5 (2X+4)=3
anonymous
 4 years ago
solve the equation ln(X3)=ln(X+2)+3 how do you cancel ln. I know when you have log you can do this= log base 5 (2X+4)=3

This Question is Closed

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Just a start and i'm not definitive on this but can you do ln( (x3)/(x+2) ) = 3 as subtracting logs equates to dividing them as one 'ln'.

TuringTest
 4 years ago
Best ResponseYou've already chosen the best response.1^that is correct then raise e to the power of both sides...

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0can you help on this problem, Ln(x3)=Ln(x+2)+3 please! so i can see it? how you do it

TuringTest
 4 years ago
Best ResponseYou've already chosen the best response.1As is stated above remember the log rule\[\log a\log b=\log(\frac ab)\]so here we can do the following:\[\ln(x3)=\ln(x+2)+3\]\[\ln(\frac{x3}{x+2})=3\]now raise e to the power of both sides and isolate x:\[\frac{x3}{x+2}=e^3\]\[x3=e^3x+2e^3\]\[xe^3x=3+2e^3\]\[x(1e^3)=3+2e^3\]\[x=\frac{3+2e^3}{1e^3}\]please pay try to follow how I did this so you can do the problems yourself in the future.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0awesome!! thx you yes, i will try myself so i can be ready for my test, right practice take perfection.thank you so much!

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0LnX+Ln(X+2)=2 this is what i did Ln(X+0)/(X+2)=2 (X+0)/(X+2)=e^2 x+=e^2X+2e^2 x+e^2x=0+2e^2 x=2e^2/x+e^2= the calculator says error cause i can not divide by o, off course, but my professor book answer is x=1.896 or x=3.896 what iam doing wrong?

TuringTest
 4 years ago
Best ResponseYou've already chosen the best response.1you have a slightly different rule applying with addition\[\log a+\log b=\log(ab)\]so here you have\[\ln x+\ln(x+2)=\ln(x^2+2x)\]try to take it from there

TuringTest
 4 years ago
Best ResponseYou've already chosen the best response.1...and you never need to add a zero like that. No point in it.

TuringTest
 4 years ago
Best ResponseYou've already chosen the best response.1Basic log rules:\[\log a+\log b=\log(ab)\]\[\log a\log b=\log(\frac ab)\]\[\log(x^a)=a\log x\]\[\log_b x=\frac{\log_a x}{\log_a b}\]these are your best friends for these kind of problems.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0so, Ln x cancel and just end up with(x+2)/(x^2+2x)?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0oh.. did you multiple (x).(x+2) and end up x^2+2x2=0 and from then do the quadratic formula?

TuringTest
 4 years ago
Best ResponseYou've already chosen the best response.1\[\ln x+\ln(x+2)=2\]\[\ln(x^2+2x)=2\]\[x^2+2x=e^2\]\[x^2+2xe^2=0\]now you can use the quadratic formula.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0thx! how about this problem e^x=35

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Take ln of both sides as ln undoes e^x.. so: ln(e^x) = ln(35) x = ln(35)

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0oh i was doing e^35 iam a little confused i though the ln cancel in both sides

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0how would you do this problem 2^3x=16 i know base is 2

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0I'm not 100% sure but if you take log(base 2) on both sides you get 3x = 4 hence x = 4/3 is that correct?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0no, is 2 to the power of 3x=16

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0yeah, that's what I did  solve that for x which gives you 4/3. type log base 2 (16) into your calculator and you'll get 4. hence 3x = 4

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0ah.. thx! what the formula for that problem?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0None  just knowing the rules of logarithms.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0i started this problem original problem is 5e^4x=500 so what i did is the following:5/5 e^4x=500/5 e^4x=e^100 4x=4.605174 4x x=.60517?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Chances are that's incorrect as answers rarely come out like that. I think this is correct: e^4x = 500/5 e^4x = 100 ln(e^4x) = ln(100) 4x = ln(100) x = ln(25) < always leave your answer in terms on ln as it is more precise than a decimal.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0I've made a mistake again.. I'm getting tired: x = ln(100) / 4

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0I understand you been tired, I been home work since 11a.m i shall also take a break. thank you so much for you help i really
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.