Question

Okay I'm almost there but the answer I'm getting is incorrect.

Answer 1

\[\ln (x)+\ln (x-2)=\ln 8\]

Answer 2

then...\[\ln (x)(x-2)=\ln 8\]

Answer 3

then...\[\ln (x ^{2}-2x)=\ln 8\]

Answer 4

then drop the ln...
\[x^{2}-2x=8\]

Answer 5

going good...

Answer 6

well you e^ both sides. That's how the ln cancel. But then you are left with a quadratic equation

Answer 7

split the two,
\[x^{2}=8\]
and
\[-2x=8\]

Answer 8

thats incorrect

Answer 9

true ok ok

Answer 10

u need quadratic formula

Answer 11

yup

Answer 12

Compare your quadratic equation with \(ax^2+bx+c=0\)
find a,b,c
then the two roots of x are:
\(\huge{x=\frac{-b \pm \sqrt{b^2-4ac}}{2a}}\)

Answer 13

x^2-2x-8=0

Answer 14

okay gimme a second to work that out.

Answer 15

sure.

Answer 16

*** and need to remember to check for valid values of x.
if you are taking ln(x) and ln(x-2) what can't x be?

Answer 17

You can always complete the square. That's another way of solving this without the long work of using the quadratic

Answer 18

2

Answer 19

whats finishing the square? Sounds like a shortcut I was denied...

Answer 20

granted

Answer 21

shortcut only if u have some prsctice.... u wanna learn that ?

Answer 22

... or just factor? \[x^2-2x-8=0=(x-?)(x+?)\]

Answer 23

practice some more then use that form

Answer 24

factoring is best here..

Answer 25

can u factor ?

Answer 26

I'll give it a shot! :)

Answer 27

sure do :)

Answer 28

go han!!!! go ku!!!! dominate the problem TEAMWORKKKK

Answer 29

? jerry ?

Answer 30

GO HAN GO KU

Answer 31

\[x^2−2x−8=0=(x−A)(x+B)\\ A*B=-8\\ A+B=-2\]
Find A and B

Answer 32

Almost there....

Answer 33

You have a system of question where you can simply plug in one equation to another if you can't see it right away. Then solve for the missing variable.

Answer 34

its (x-4)(x+2)

Answer 35

thats correct :)

Answer 36

so what are 2 values of x u got ?

Answer 37

ten solving its 4 and -2

Answer 38

\[(x-4)(x+2)=0\]

Answer 39

and -2 would be extraneous

Answer 40

but can x be -2 ?? think ....

Answer 41

yes, so x is only = ?

Answer 42

4?

Answer 43

yup, u got it :)

Answer 44

HAZUAHH!

Answer 45

THanks everyone! I really appreciate it! :)

Answer 46

welcome ^_^