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1. Simplify fully (√𝑎 + √4𝑏)(√𝑎 − 2√𝑏)
2. (Original post by error405)
Simplify fully (√𝑎 + √4𝑏)(√𝑎 − 2√𝑏)
So simplify
3. (Original post by error405)
Simplify fully (√𝑎 + √4𝑏)(√𝑎 − 2√𝑏)
First look at . How can you simplify / write it in a different way?
4. (Original post by error405)
...
Hi, please don't create duplicate threads - I have removed the thread you just created. If you still need help, please post all your working that you have tried.
5. (Original post by Notnek)
Hi, please don't create duplicate threads - I have removed the thread you just created. If you still need help, please post all your working that you have tried.

√4B=2b right??
6. (Original post by error405)

√4B=2b right??
Just checking sincce your original question isn't clear. Do you mean

or

I assumed it was the second one...
7. my working out:

a+2√ab+2b√a-4b√b
8. (Original post by Notnek)
First look at . How can you simplify / write it in a different way?
Multiply the brackets out to begin with
9. (Original post by Notnek)
Just checking sincce your original question isn't clear. Do you mean

or

I assumed it was the second one...

yes the 2nd one
10. (Original post by error405)

√4B=2b right??
No. 2b would be square root 4b^2
11. (Original post by error405)
yes the 2nd one
Okay so

It then becomes

Can you now try multiplying out the brackets? Post all your working if you get stuck.
12. (Original post by 12ksmith)
Multiply the brackets out to begin with
I recommended simplifying that term before expanding because then you have something of the form and it's easier to expand.
13. (Original post by Notnek)
I recommended simplifying that term before expanding because then you have something of the form and it's easier to expand.

Well yeah, you could simplify the left bracket to where root 4b becomes 2 root b. I guess that could make it a little simpler. But you would have to multiply out anyways.

Personally I would find this easier to multiply out first then simplify from there.
14. (Original post by Notnek)
Okay so

It then becomes

Can you now try multiplying out the brackets? Post all your working if you get stuck.
a-2√ab+2√ab-4√ b
15. (Original post by error405)
a-2√b-2√ab+2√ab-4√ b
a-4√ b
16. Thank you
17. (Original post by error405)
a-4√ b
Nearly but does not give . Have another go at this.

Also please try to use brackets more in your posts e.g. instead of √ab, write √(ab) because √ab looks like , which is not what you mean.
18. (Original post by Notnek)
Nearly but does not give . Have another go at this.

Also please try to use brackets more in your posts e.g. instead of √ab, write √(ab) because √ab looks like , which is not what you mean.
is it (4b) ?
19. (Original post by error405)
is it (4b) ?
Correct
20. a - (4b)

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