lolz pre-calc halp

[Silverhawk79]

Yeah, I'm into logs and stuff now...and I don't get this problem:
Solve algebraically: ln(x+4) - ln(x-2) = lnx
I probably just didn't take good enough notes, but help would be appreciated.

[Rius]

Yeah, I'm into logs and stuff now...and I don't get this problem:
Solve algebraically: ln(x+4) - ln(x-2) = lnx
I probably just didn't take good enough notes, but help would be appreciated.

ln(x+4) - ln(x-2) = lnx
ln[(x+4)/(x-2)] = lnx
(x+4)/(x-2)=x

Quotient & Equal Property Rules, FTW. You can do the rest. ^_^

[QuickKarel]

Yeah, I'm into logs and stuff now...and I don't get this problem:
Solve algebraically: ln(x+4) - ln(x-2) = lnx
I probably just didn't take good enough notes, but help would be appreciated.

ln(x+4) - ln(x-2) = lnx
ln[(x+4)/(x-2)] = lnx
(x+4)/(x-2)=x

Quotient & Equal Property Rules, FTW. You can do the rest. ^_^

O_O I wish I could do that with my pre-algebra skills. -__-

[Silverhawk79]

Yeah, I'm into logs and stuff now...and I don't get this problem:
Solve algebraically: ln(x+4) - ln(x-2) = lnx
I probably just didn't take good enough notes, but help would be appreciated.

ln(x+4) - ln(x-2) = lnx
ln[(x+4)/(x-2)] = lnx
(x+4)/(x-2)=x

Quotient & Equal Property Rules, FTW. You can do the rest. ^_^

No way, we JUST went over that.
My notes suck. >_>

[BOSSNIG]

Yeah, I'm into logs and stuff now...and I don't get this problem:
Solve algebraically: ln(x+4) - ln(x-2) = lnx
I probably just didn't take good enough notes, but help would be appreciated.

ln(x+4) - ln(x-2) = lnx
ln[(x+4)/(x-2)] = lnx
(x+4)/(x-2)=x

Quotient & Equal Property Rules, FTW. You can do the rest. ^_^

O_O I wish I could do that with my pre-algebra skills. -__-

QFT, but wait, Im in Pre-algebra a year early :o.

[Pokesamrus]

Yeah, I'm into logs and stuff now...and I don't get this problem:
Solve algebraically: ln(x+4) - ln(x-2) = lnx
I probably just didn't take good enough notes, but help would be appreciated.

ln(x+4) - ln(x-2) = lnx
ln[(x+4)/(x-2)] = lnx
(x+4)/(x-2)=x

Quotient & Equal Property Rules, FTW. You can do the rest. ^_^

O_O I wish I could do that with my pre-algebra skills. -__-

WHAT THE HELL? pre-algebra?

I took that poop in 5th grade and some in 6th.

[Silverhawk79]

I'm feeling dense tonight, and can't remember how to divide out fractions like that. -_-;

[Jono2]

we did that earlier this year.

ln(x+4) - ln(x-2) = ln(x)

ln(x+4)/(x-2) = ln(x)

at this point, IIRC, you can de-log both sides.

x+4/x-2 = x



remember, any log added to another log is a multiplication.  any log subtracted from another is a division.


ln is the same as log, except that log has a base of 10 and ln has a base of n.

[Silverhawk79]

we did that earlier this year.

ln(x+4) - ln(x-2) = ln(x)

ln(x+4)/(x-2) = ln(x)

at this point, IIRC, you can de-log both sides.

x+4/x-2 = x



remember, any log added to another log is a multiplication.  any log subtracted from another is a division.


ln is the same as log, except that log has a base of 10 and ln has a base of n.

I KNOW BUT I CAN'T REMEMBER WHAT TO DO TO FURTHER SIMPLIFY THE FRACTION

[Jono2]

multiply it out...


x = x+4/x-2

x( x - 2) = x + 4

x² - 2x = x + 4

x² - 3x - 4 = 0


quadratic formula or factoring is the next step towards X.

but you don't need the quadratic formula, because it's

(x + 1) (x - 4)

and you can't have a negative log

so x is equal to 4.

[Silverhawk79]

multiply it out...


x = x+4/x-2

x( x - 2) = x + 4

x² - 2x = x + 4

x² - 3x - 4 = 0


quadratic formula or factoring is the next step towards X.

but you don't need the quadratic formula, because it's

(x + 1) (x - 4)

and you can't have a negative log

so x is equal to 4.

Oh. I just multiplied it wrong.
Lulz.

[Daft Pink]

Yeah, I'm into logs and stuff now...and I don't get this problem:
Solve algebraically: ln(x+4) - ln(x-2) = lnx
I probably just didn't take good enough notes, but help would be appreciated.

ln(x+4) - ln(x-2) = lnx
ln[(x+4)/(x-2)] = lnx
(x+4)/(x-2)=x

Quotient & Equal Property Rules, FTW. You can do the rest. ^_^

O_O I wish I could do that with my pre-algebra skills. -__-

WHAT THE HELL? pre-algebra?

I took that poop in 5th grade and some in 6th.

Me too. I'm in an Algebra 1 Honors class. :| And I'm in 7th grade.