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**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 21,330

#1. What is the value of

?#2. What is the value of

?#3. What is the value of

?#4. If

,what is the value of x?

#5.What is the value of

?#6. If

,what is the value of x?

#7. If

,then what is the value of

?

#8.What is the value of

#9.If

then

(1)

(2)

(3)

(4) None of these

#10. If log 2 = x, log 3 = y, and log 7 = z, then what is the value of

#11. If

,then what is the value of x?

#12. What is the value of

?#13. If

,then what is the value of

?

#14. If log 27 = 1.431, what is the value of log 9?

#15. If

,and ,

then what is the value of x?

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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**glenn101****Member**- Registered: 2008-04-02
- Posts: 108

1.

2^x=16

2^x=2^4

=4

2.

343^x=7

343^x=343^1/3

=1/3

4.

x^-1/2=9/16

x^-1/2=256/81^-1/2

x=256/81

*Last edited by glenn101 (2008-12-19 15:28:23)*

"If your going through hell, keep going."

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**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 21,330

glenn101,

All correct! Very well done!!!

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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**careless25****Real Member**- Registered: 2008-07-24
- Posts: 559

3.

log sqrt(232)

= .5 log 232

= 1.183

5. log sqrt(8)/log 8

= 0.5 log 10 (8)/ log 10 (8)

= 1/2

i think..

6. log 32 x = 0.8

32 ^0.8 = x

16 = x

8.

a) log 5 (5) = 1

b) log4 (9)

= log 10 (9)/ log 10 (4)

= 1.585

c) log 3 (2)

= log 10 (2) / log 10 (3)

= 0.631

1 * 1.585 * 0.631 = 1.000

9.

a^x = b^y

a)y log a (b) = x

log a (b) = x/y

log 10 (b)/ log 10 (a) = x/y

b)x log b (a) = y

log b (a) = y/x

log 10 (a)/ log 10 (b) = y/x

so i think the right answer is (3)

12. 16 ^ (log 4 (5))

16 ^ (log 10 (5) / log 10 (4))

= careless25 :D

13. If log 10 (7) = a

then log 10 (1/70) = a - 2a - 1

= -1.8451

14.

if log 27 = 1.431

then log 9 = 1.431/1.5

log 9 = 0.954

because 9 ^ 1.5 = 27

15. same reasoning as above

if log 10 (3) = .477

then 1000^ x = 3

log 1000 (3) = x

log 1000 (3) = .477/3

x = .159

because 10 ^ 3 = 1000

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**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 21,330

Well done, careless25!

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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**glenn101****Member**- Registered: 2008-04-02
- Posts: 108

It's good to see other people attempting these questions:)

They are very helpful for revising my maths, thanks ganesh!

"If your going through hell, keep going."

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