Solving Logarithmic Equations - Example 1

[tippman2k01]

thank you so much! im gonna ace my final thanks to you

[fat2thecop]

thank you, i have exam retake coming up in a couple of days and you are a great help

[dwboy]

I don't understand why x = -3 is an extraneous answer when log_3((-3)^2) is valid and causes LHS = RHS.

[eg6racer101]

@dwboy u cant hav the log of any negative #

[2dreambig22]

@dwboy the negative 3 is squared causing it to cancel out the negatives and making it into positve that is why it works

[MrMistermister101]

love ur videos always available and simple. Keep up the good work.

[patrickJMT]

@MrMistermister101 glad you like ' em : )

[paranoid711]

I love you lol. Thanks so much my math teacher is a very poor teacher, unfortunately.

[patrickJMT]

@paranoid711 well, you can come back and watch any time : )

[MrApplemonster1]

This really helped me! thank you random internet person who's probably a teacher!(:

[mirjettaaa]

Thanks a lot

U really helped me!!

[Denali1994]

man thanks a lot this really helped me

[mrgrant888]

I've been going over this in my book. Thanks for clearing this up. You are the MAN!!!

[Syruscleat]

I see.

[Canouver]

I don't get how you went from log_3(x^2/x+6) = 1 to 3=(x^2/x+6)

Can you please explain? Like what rule did you use?

[patrickJMT]

@Canouver well, one can convert from exponential to log notation and vice versa. i am just using that formula. i have a video 'properties of logarithms ' you might check out -

[Canouver]

@patrickJMT Oh I see! It's the log_ab=y is equal to b=a^y. Right?

[patrickJMT]

@Canouver yep, that is correct

[Neutrinoghost]

Do you know of any places (websites or videos) where I can learn to factorise, I really have an issue with it.

[patrickJMT]

@Neutrinoghost not off the top of my head, i am search there are a few out there that discuss it

[djancak]

Wouldn't the logarithm 2·log_3(-3) = log_3(9), making it a non-extraneous answer?

[patrickJMT]

@djancak no, it is extraneous. you have to think about the domain of log _3(x)