Solving logarithmic equations

[mysstring1]

why do we need to check the solutions for x?

do we always check it by subing it back to the original equation? but why ? it doesn't make sense that a quadratic gives you answers (which is all supposed to be right answers) that does not satisfy the original equation. why are we getting extraneous solutions>?

[mysstring1]

a question^^ why does ln e^2/3 giving us 2/3??

and -e^-ln7=1/7? could you explain this in detail please^^

[ChemR805]

muah, bella, that was perfect

[PrinceT300]

man why dont i understand this?!

[LovePeaceSmile15]

Amazing , you have no idea how much that helped me !

[zivstarosta]

korean voice. thanks alot you helped me cover the basics for my exam :)

[zivstarosta]

I have a question: if i have lograthims in both sides of the equations?

[MinusTheNumber]

FINALLY! Thank you so much! I've been stuck on a question like this and didn't realized until now that I was turning the equation into a '0=' too soon.

Thanks a lot! I really appreciate the video!

[Champerbutt]

in the equation in the top comment (for me) 3log3(x+4)-log3(9)=2 if it is 3log base(b)3 (x+4) -log(b)3 (9)=2 since log(b)3 (9) = 2 then 3log base(b)3 (x+4)=4. what do i do from here???

[7164227]

thanks that was very helpful ^_^

[PhreshNess99]

also, I used the cancellation law with: ln(2+x) = 2/3 to make e^ln(2+x)= e^2/3. So I was left with 2+x = e^2/3 so I calculated the number on the right. which gave me 2.463. then I substracted 2 from both sides, giving me x = 0.463. but then when I wanted to check it...it was wrong :S

[PhreshNess99]

See what I don't get is: you have 3ln(2+x)...why do you divide both sides instead of raising the 3 to the power of ln(2+x)^3 how am I supposed to know ehn to divide both sides or when to raise to it to a power...:S

[pyrodudewasa]

can someone help me how to get the components in order to graph: f(x)=ln((x+2)/(9x-8)) ive been looking for a program to graph this but it does not recognize it... HELP PLEASE i need this for tomorow... atleast some link to a program or a similar tutorial vid of these types of logs

[unLOVEYY]

How do you go about simplifying a logarithmic equation with different bases? I'm given the equation:

log base 5 (x+1) + log base 3 (x+4) = 2

[Apelsinskal90]

How do I solve ln(x^3+2x)-3ln(x)? I get it this far: ln((x^3+2x)/(x^3)) How do I continue?

[TheLoveformankind]

good video

[RECTmetal]

Thank you veryveryvery much! A very helpful lesson that my teacher failed to make me understand! =]

[2race4life]

Very good helpful video to clarify your log skills

[84Porsche944]

learned exactly what I needed. thanks! and like everyone else said, nice voice

[anujbarca]

Nice tutorial nice voice :)

[Rigwave]

@marlove31 you put log in front of both sides of the equation and move the respective exponents in front of the log.

For example: 4^3 becomes 3log 4

[marlove31]

what if there are no logs to begin with? like this. it says to solve for x. 13^9x=2^-x-5. (this ^ means raised in this case)

[kaitoukidsama95]

haha......do u believe it or not,,,my teachers oftenly skip classes to attend meetings tht only teaches her students logarithm in 3 hours class for whole chapter 2 days before examination.....and luckily i was absent that day so i never learn logarithm from her until today...but i manage to learn it all by myself using the text book and i can answer all the question about logarithm..but the problem is,,,,after the exam i cant remember a thing wht i learn from the text book.......why is tht?

[lukinu2]

thanks a lot, a haven't managed to understand a thing in 3 weeks with my teacher and i understood these logs in 10 mins... thanks :)

[latinaprincezza123]

you are better than my actual teacher

[ShEShAShii]

What if the equatioon is:

log base 5 (4-x/3)^2=0.007 !?

[crazypsyco88]

boringgggggggggggggggggggggggg­gggggggggggggggggggggggg



[Biggiedafirst]

what about; logx = 2.4

[everymanComics]

thank you so much!

[ImUrNightTerror]

damn love the voice wish my teacher spoke like that, would never sleep in my math class again

[lemartzky123]

how it becomes 2/3 on 8:00 ?

[lemartzky123]

is that 6x or bx? ><,

[mmanch01]

Lady, you need to speak up. Having a summary of the technique(s) you are employing wouln't hurt...

[zild3000]

you're awesome!!!!

[tashfiq1993]

i like it when you refer to the numbers as "this guy"

[HolyPantsMcTavish]

Great, great, great!!! I've been pulling my hair out over these logarithmic equations with coefficients and you have saved me from any further cranial bruising. Thank you!

[RuDofCAraVAn]

urm... if its not it logarithm form ? its like this:

2x^-3/4 = 54

how do i solve it?

sorry, bad english

[mgomez6409]

what if the equation is 3log3(x+4)-log3(9)=2

[rlp85hotmail]

@mgomez6409 First bring up the coefficient of 3 on the left as an exponent:

log(3(x+4))^3 - log3(9) = 2. Then simplify to make things easier for you:

log3^3(x+4)^3 - log27 = 2, so log27(x+4)^3 - log27 = 2. Next, condense the logarithmic expressions on the left: log27(x+4)^3/27 = 2. Simplify:

log(x+4)^3 = 2. Then do as I showed in the video, noting that the base of this logarithm is 10.

[Zorglian]

what if the equation is:

2log4-1/3log8=log(x)

[rlp85hotmail]

@Zorglian First you bring up the coefficients on the left side as exponents:

log 4^2 - log 8^1/3 = log x. Next, simplifiy the exp. terms:

log 16 - log 2 = log x. Next, condense left side:

log 16/2 = log x. This becomes

log 8 = log x. Hence, x = 8. In summary, you condense the log expressions on each side of the equation using properties of logarithms.

[dubbersubber]

thanks, helps quite a bit

[DrLuveh]

Love your sexy voice. Thanks for the lesson got it!

[ojoreakatheoj]

This is an excellent video. With that said, I must point out that the narration sounds like the shy girl from Napoleon Dynamite. Absolutely awesome.

[sullivanseven]

Very good. keep on the good job

[sinus2alfa]

this is so easy take a harder example

[wangzishow]

What if the equation is :

logx32 = 5/6 ?

[rlp85hotmail]

Write in exponential form: x^(5/6) = 32. Then raise both sides to the power of 6/5.

[SpartonRecords]

@game2heart thx

[wh0iskarl]

what if theres 2 logs like logx +log(x-5) = log6

[rlp85hotmail]

You need to condense the left side as log(x(x-5)) and then equate the inputs of the two logs. The only way for log a to equal log b is for a to equal b.

[megtheamazing]

thank youu

[SpartonRecords]

i don't understand what happened to the other log 6. did it jus dissappear ? plz help me

[TerryAdam1993]

changed it to an exponential.

log base 6 of 2 = 6squared

[game2heart]

@SpartonRecords It didnt disappear. The 2 terms on the left side has the same base of log base 6, thats why the top terms are multiplied together, leaving log base 6 as the base term.

[1994soro]

You Save my life :D

[Bigpimpof808]

if you listen in the background it sounds like shes at a strip club or something. constant beats. lol

[Bigpimpof808]

oh shit nvermind, its my computer, lol.

[18cooler]

good stuff!

[bren7473]

Stop being creepy about her voice. Jesus Christ you guys are weird.

[MexicanSavior]

you're voice is so beautiful that many words can describe how rpetty ur voice , u should post a pic.

[kosanovskiy]

dude wtf????

fucking stalker she helping us with math ...not proclaiming prostitution LOL

you fucking dumb LOL

[11Rossifumi]

lol

[sabayak]

Thanks a lot. Helps me out.

[El316]

Arigatou! This video has helped me out a lot!!!! And i'm stressing A LOT! ARIGATOU!

[jesusclau1]

very nice video...thank you for all your help!!!

[PepperShkr]

I know I'm not the only one but you sound so HOT but besides that IVE LEARN SO MUCH. I hope your not insulted of offended by that comment.

[psyscleuno]

Has anybody told you that you have the sexiest voice!!! and omg your awesome in math!!!! The perfect girlfriend!!!

[ShaddyLee]

Thank you !!! love logarithm equations

[absterz]

excellent question, that worked out beautifully. kudos

[djhuab]

Thank you so much!!

[darylicked]

you need to keep the divided number in the equation. if its an X, you loose a value this way.

[awet300]

thank you very much!!

[chikano97]

Thank You So Much.........:)

[PortugalTheAccount]

Marry me?

[Mizbonita08]

thanks so much =)

[chonzor]

i want you

[MrPiPPo]

i love you.

[jemeni12345]

YOU ARE MY HERO

[speranforever]

THANK YOU! you're a great help!

[Chipsnsoda]

Your voice is soooo soothing it actually relaxed me to learn. Did not feel stressed or anything. Thank you so much :)

[reddongton]

ty my professor can't teach

[korrisha]

Very very useful girl you are sooo kind It helped me sooo much better than my boring professor love K

[jijiks]

thanks!!love your voice...sexy...

[jancute00]

w8....i am confuse...look...if u will transfer the x to the other side it will become division...or if the sign is addition it must be subtraction if u will transfer...y it becomes multiplication when u transfer the x...??

im just confused...

[Nano022289X]

its because its one of the rules that are applied to this equation. i got confused but i saw the rules on my book

[2high2aim]

thanks a lot

[daddylench]

that was awesome! very good teaching thank you!

[pablolinyang871]

thanks dr. parsons

[rodrigito1978]

Thanx!!!!

[hanseru]

sexy voice baby... i love it...

[LiquidJello090]

@hanseru o_o

[Musiclo0ovee]

@hanseru me too