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# indices

1. work out the value of x when

2^30/8^9=2^x

how would i do this
2. Replace 8 with 2^3.
3. (Original post by little_wizard123)
Replace 8 with 2^3.
ok so 2^30/2^3=2^x
4. (Original post by zed963)
work out the value of x when

2^30/8^9=2^x

how would i do this

Remember, , hence, can be written as
Now use the law,
5. (Original post by zed963)
ok so 2^30/2^3=2^x
No. You have replaced 8^9 by 2^3.

8^9 = (2^3)^9. Then simplify this with an indices rule.
6. (Original post by raheem94)

Remember, , hence, can be written as
Now use the law,
so 2^30-2^27=2^3
7. (Original post by zed963)
so 2^30-2^27=2^3
Is the '-' a typo?
It should be a divisor.

Yes, we get , but what is the value of
8. (Original post by raheem94)
Is the '-' a typo?
It should be a divisor.

Yes, we get , but what is the value of
Yeah it's a typo

x=3
9. 2^30 / 8^9 = 2^x
2^30 / (2^3)^9 = 2^x
2^30 / 2^27 = 2^x
2^3 = 2^x

x = 3
10. (Original post by zed963)
Yeah it's a typo

x=3

You are getting better at maths!
11. (Original post by kuroudo93)
2^30 / 8^9 = 2^x
2^30 / (2^3)^9 = 2^x
2^30 / 2^27 = 2^x
2^3 = 2^x

x = 3
You may like to have a look at the forum rules, full solutions are considered a last resort.

So always first give hints, please don't post full solutions.
12. just expand 2^30 and divide it by 8^9 and you'll get 8. therefore x is 3
13. (Original post by lmartynofficial)
just expand 2^30 and divide it by 8^9 and you'll get 8. therefore x is 3
Can you please clarify what do you mean by expand 2^30?
14. (Original post by lmartynofficial)
just expand 2^30 and divide it by 8^9 and you'll get 8. therefore x is 3
You make it sound easy.
15. (Original post by raheem94)
Can you please clarify what do you mean by expand 2^30?
I think he literally means do 2*2*2*2.... 30 times and write the value without indices. And then the same with 8^9
16. (Original post by hassi94)
I think he literally means do 2*2*2*2.... 30 times
My also guess was that he means this, but it doesn't looks sensible.

How will he divide by 8^9, any idea?
17. (Original post by raheem94)
My also guess was that he means this, but it doesn't looks sensible.

How will he divide by 8^9, any idea?
It is a pretty terrible solution to the problem.

Well you get 1073741824/134217728 and then he somehow sees that that = 8.

It's a silly solution, I wouldn't worry
18. (Original post by hassi94)
It is a pretty terrible solution to the problem.

Well you get 1073741824/134217728 and then he somehow sees that that = 8.

It's a silly solution, I wouldn't worry
That solution does actually work.
19. (Original post by hassi94)
It is a pretty terrible solution to the problem.

Well you get 1073741824/134217728 and then he somehow sees that that = 8.

It's a silly solution, I wouldn't worry
At least he isn't trying to use the infinity concept someone used yesterday. lol

20. (Original post by zed963)
That solution does actually work.
We know it works, but how will you do it without a calculator?
You won't be able to see that the value is 8 without a calc.

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