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# !URGENT! 1 question on Surds! GCSE! watch

1. I cant complete this final question could someone help me how to get the final answer which is -5+4√3 (calculator^^)

THX!!!!!!
p.s. its A* Q6
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2. Rationalising means you remove the denominator by multiplying the entire fraction by it, i.e. multiply top and bottom by root 3.
3. (Original post by NikolaT)
Rationalising means you remove the denominator by multiplying the entire fraction by it, i.e. multiply top and bottom by root 3.
I know that I've even done the other questions correctly it just this one where i'm doing something wrong and that means i cannot get the right answer.

When I've done what you said I've now got 12-5+3/3 this is where i don't know what to do. :/
4. (Original post by moththecat)
I know that I've even done the other questions correctly it just this one where i'm doing something wrong and that means i cannot get the right answer.

When I've done what you said I've now got 12-5+3/3 this is where i don't know what to do. :/
When you multiply the numerator by what do you get

Remember you have to multiply both bits
5. (Original post by TenOfThem)
When you multiply the numerator by what do you get

Remember you have to multiply both bits
12-5= 12-5+3
6. (Original post by moththecat)
12-5+= 12-5+3
The numerator is 12 - 5root3

What do you get when you multiply 12 by root 3

What do you get when you multiply 5root3 by root3 .... You started doing this correctly but then turned 5root9 into 5+root9 ... Why
7. (Original post by TenOfThem)
The numerator is 12 - 5root3

What do you get when you multiply 12 by root 3

What do you get when you multiply 5root3 by root3 .... You started doing this correctly but then turned 5root9 into 5+root9 ... Why
A) What do you get when you multiply 12 by root 3 = 12√3
B)
What do you get when you multiply 5root3 by root3 = 5√9

so what now?
8. (Original post by moththecat)
A) What do you get when you multiply 12 by root 3 = 12√3
B)
What do you get when you multiply 5root3 by root3 = 5√9

so what now?
You know what root9 is so simplify 5root9

Then divide both bits by 3 since you had 3 in the denominator
9. (Original post by moththecat)
I cant complete this final question could someone help me how to get the final answer which is -5+4√3 (calculator^^)

THX!!!!!!
p.s. its A* Q6
Hope this helps!
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10. (Original post by SaiDuc)
Hope this helps!
Presumably you are unaware that full solutions are against the forum guidelines
11. (Original post by TenOfThem)
You know what root9 is so simplify 5root9

Then divide both bits by 3 since you had 3 in the denominator
That wont get me -5+4√3 what you said will get me 12-5√3
12. (Original post by moththecat)
A) What do you get when you multiply 12 by root 3 = 12√3
B)
What do you get when you multiply 5root3 by root3 = 5√9

so what now?

(Original post by moththecat)
That wont get me -5+4√3 what you said will get me 12-5√3
You need to divide the responses you gave in the first quote by 3. NOT root3
13. (Original post by TenOfThem)
Presumably you are unaware that full solutions are against the forum guidelines
I was unaware of this. Thanks for telling me!

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