log question help please!!! (1 Viewer)

[wats]

log10 x^6 – 8 = 3log10x orthat is log base ten x to the power of six subtract eight equals three times log base ten x.sorry about the format thanks for help.

 

[alexvincent]

log10 x^6 – 8 = 3log10x orthat is log base ten x to the power of six subtract eight equals three times log base ten x.sorry about the format thanks for help.

Solution:
6logx - 3 = 3logx
6logx - 3logx = 3
3logx = 3
logx = 1
x = 0
The base of the log is irrelevant.
Anything to the power of 1 is 0.
So logx = 1 => x = 0 ALWAYS.

 

[tonyharrison]

Solution:
6logx - 3 = 3logx
6logx - 3logx = 3
3logx = 3
logx = 1
x = 0
The base of the log is irrelevant.
Anything to the power of 1 is 0.
So logx = 1 => x = 0 ALWAYS.

Wasn't the question (-8) not (-3) ?
I got:
log(Base 10) = log
So, logx^6 - 8 = 3logx
6logx - 8 = 3logx
8 = 6logx - 3logx
8 = 3logx (2 - 1)
8 = 3logx
8/3 = logx
Using one of the log rules:
x = 10^(8/3)
(remember log has a base of 10)
I think this works out...sorry for the formatting!

 

[wats]

Solution:
6logx - 3 = 3logx
6logx - 3logx = 3
3logx = 3
logx = 1
x = 0
The base of the log is irrelevant.
Anything to the power of 1 is 0.
So logx = 1 => x = 0 ALWAYS.

when i put zero back into the initial eqn it doesnt come out as expected with trial and error i got it to approx 33.5 any other suggestions?

 

[wats]

Wasn't the question (-8) not (-3) ?
I got:
log(Base 10) = log
So, logx^6 - 8 = 3logx
6logx - 8 = 3logx
8 = 6logx - 3logx
8 = 3logx (2 - 1)
8 = 3logx
8/3 = logx
Using one of the log rules:
x = 10^(8/3)
(remember log has a base of 10)
I think this works out...sorry for the formatting!

that is the answer that i got but when i put the value (10^8/3) back into the equation it doesn't work out, any other suggestions, by trial and error i got it to approx 33.5

 

[tonyharrison]

that is the answer that i got but when i put the value (10^8/3) back into the equation it doesn't work out, any other suggestions, by trial and error i got it to approx 33.5

That's weird, when i put it back into the equation, both sides equal 8. Are you sure you put it in correctly?

 

[benjihua93]

was the answer x=2