You are Here: Home >< GCSEs

# How to turn 8^9 into 2^x

Announcements Posted on
Would YOU be put off a uni with a high crime rate? First 50 to have their say get a £5 Amazon voucher! 27-10-2016
1. This is the question I'm working on - 2^30 / 8^9 = 2^x. Work out the value of x. My revision book has given me a tip saying "convert 8 to a power of 2 and then use the index laws". I can't remember how to do that, so could anyone remind me please?
2. 8= 2 x 2 x2 so 2^3

8^9= (2^3)^9= 2^27

2^x = 2^30/2^27 = 2^3
3. So how do you get 8 from 2?

Spoiler:
Show
2x2x2
4. 8 is 2^3. So (2^3)^9 is...
5. (Original post by AxSirlotl)
This is the question I'm working on - 2^30 / 8^9 = 2^x. Work out the value of x. My revision book has given me a tip saying "convert 8 to a power of 2 and then use the index laws". I can't remember how to do that, so could anyone remind me please?
Remember that , so then you are dealing with . From here, simply apply the division rule for indicies
6. Hmmm............ I'm not QUITE sure if someone else has already said it, but I THINK the fact that might help. Just a hunch though.
7. 8^9 = 2^x

8 = 2^3

8^9 = (2^3)^9

(a^b)^c = a^(b*c)

(2^3)^9 = 2^27
8. (Original post by AxSirlotl)
This is the question I'm working on - 2^30 / 8^9 = 2^x. Work out the value of x. My revision book has given me a tip saying "convert 8 to a power of 2 and then use the index laws". I can't remember how to do that, so could anyone remind me please?

there is a rule in ur book which goes something like this
therefore

so x = 3

Watch this video if you don't understand

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: September 6, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### University open days

Is it worth going? Find out here

Poll
Useful resources

## Study tools

### Essay expert

Learn to write like a pro with our ultimate essay guide.

See where you can apply with our uni match tool

### Make study resources

Create all the resources you need to get the grades.

### Create your own Study Plan

Organise all your homework and exams so you never miss another deadline.

### Resources by subject

From flashcards to mind maps; there's everything you need for all of your GCSE subjects.

### Find past papers

100s of GCSE past papers for all your subjects at your fingertips.