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C2 Logs... I hate them and need help Watch

1. (log3(81)+log3(243))/(log3(x)) = log3(x)

Need urgent help with this one.After simplifying the numerator, do I multiply both sides by log3(x) ?
2. (Original post by kieton123)
(log3(81)+log3(243))/(log3(x)) = log3(x)

Need urgent help with this one.After simplifying the numerator, do I multiply both sides by log3(x) ?
check my solution
3. (Original post by kieton123)
(log3(81)+log3(243))/(log3(x)) = log3(x)

Need urgent help with this one.After simplifying the numerator, do I multiply both sides by log3(x) ?
Yes multiply both sides by log3x

you should end up with log3x squared =9

now square root both sides

log3x= +- 3

solve from there
4. (Original post by kieton123)
(log3(81)+log3(243))/(log3(x)) = log3(x)

Need urgent help with this one.After simplifying the numerator, do I multiply both sides by log3(x) ?
3^4 = 81 and 3^5 = 243

let log3(x) be y and make a quadratic equation by multiplying everything by y
i got x as 243 and 1/3.
5. (Original post by RizK)
3^4 = 81 and 3^5 = 243

let log3(x) be y and make a quadratic equation by multiplying everything by y
i got x as 243 and 1/3.
Apparently x is 27, Imran got the answer
6. (Original post by kieton123)
Apparently x is 27, Imran got the answer
I just checked and this is the way they have done it in the C2 book... mind telling me where you got the question from? thanks
7. (Original post by RizK)
3^4 = 81 and 3^5 = 243

let log3(x) be y and make a quadratic equation by multiplying everything by y
i got x as 243 and 1/3.

8. If , then

You can verify your answer by plugging x back into the original equation and seeing if both sides output the same value.
9. (Original post by RizK)
I just checked and this is the way they have done it in the C2 book... mind telling me where you got the question from? thanks
Ok man, its the "Revise Edexcel AS Mathematics AS Workbook"
10. Og my god i read the question wrong xD I thought log3(81)was a serparate terrm lol
Cheers!
11. (Original post by Reda2)
You're missing a solution >
You must also consider
12. (Original post by edothero)
You're missing a solution >
You must also consider
Just wanted to show him the solution, pretty sure he knows that.

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