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# New Maths GCSE 9 -1 Exam Style Question, NEED HELP!!! watch

1. Hey Everyone,
I was doing some revision and I stumbled on this question. I have never seen an unknown in an indices. I know how to rearrange for x and all of that (cuz im in yr11..duuh) lol anyways the question is:
3^2x = 1/81

Any help?
2. (Original post by NothingButWaleed)
Hey Everyone,
I was doing some revision and I stumbled on this question. I have never seen an unknown in an indices. I know how to rearrange for x and all of that (cuz im in yr11..duuh) lol anyways the question is:
3^2x = 1/81

Any help?
At GCSE, you can't rearrange to solve these.

3. (Original post by notnek)
At GCSE, you can't rearrange to solve these.

OK i understand but then it says 2x?
4. Look up logarithms
5. (Original post by NothingButWaleed)
OK i understand but then it says 2x?

Since the solution to is , for the above equation you need so .

Can you try that for your question?
6. (Original post by Danielelliston)
Look up logarithms
They're not part of GCSE. This question is meant to be done by considering powers of 3.
7. (Original post by NothingButWaleed)
Hey Everyone,
I was doing some revision and I stumbled on this question. I have never seen an unknown in an indices. I know how to rearrange for x and all of that (cuz im in yr11..duuh) lol anyways the question is:
3^2x = 1/81

Any help?
re write the rhs with a base of 3 to start with
8. OHHHHHH!!!!,

So if there is a 3, i need to do 3^4 to get 81, but if there is a 2x i need an integer which will give me 4 when multiplied by 2, that number is 2
But to get a fraction I need a negative indices so I will need -2

Hence,
3^2(-2) = 1/81

There!
9. (Original post by notnek)
At GCSE, you can't rearrange to solve these.

how do u use the different maths symbols?
10. (Original post by Zxrxh)
how do u use the different maths symbols?
use "latex" tags to get the different maths symbols...check this website out to see how to use them:
https://www.thestudentroom.co.uk/wiki/LaTex

11. (Original post by NothingButWaleed)
use "latex" tags to get the different maths symbols...check this website out to see how to use them:
https://www.thestudentroom.co.uk/wiki/LaTex

To add to this, you can click on the expressions to see what code was used to format them
12. (Original post by NothingButWaleed)
use "latex" tags to get the different maths symbols...check this website out to see how to use them:
https://www.thestudentroom.co.uk/wiki/LaTex

thnxx
13. How do you make t the subject of the formula v = u +at.
14. (Original post by Zxrxh)
How do you make t the subject of the formula v = u +at.
ok..so basically we know that at = a*t therefore to isolate t we would need to divide both sides of the equation by a..giving us

then we would need to subtract "u" from both sides to, again, isolate "t" so we would get the new equation:

15. (Original post by NothingButWaleed)
ok..so basically we know that at = a*t therefore to isolate t we would need to divide both sides of the equation by a..giving us

then we would need to subtract "u" from both sides to, again, isolate "t" so we would get the new equation:

oh yeah thanks, that was like a grade 3
16. (Original post by Zxrxh)
oh yeah thanks, that was like a grade 3
lol yh no worries
17. (Original post by NothingButWaleed)
ok..so basically we know that at = a*t therefore to isolate t we would need to divide both sides of the equation by a..giving us

then we would need to subtract "u" from both sides to, again, isolate "t" so we would get the new equation:

You didn't divide both sides by correctly.

(Original post by Zxrxh)
oh yeah thanks, that was like a grade 3
18. (Original post by RDKGames)
You didn't divide both sides by correctly.
so what would the answer be ??
19. im failing maths 100%
20. (Original post by Zxrxh)
so what would the answer be ??

Dividing both sides a:

Split the fraction on the RHS into 2 different ones with the same denominator. Simplify where appropriate. Rearrange.

Have a go.

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Updated: November 26, 2017
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