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Stuck on A level Maths question :S

Simplify (2+√5) / (3-√7)

I got stuck on this, I tried to rationalise the denominator and got: (6+2√7+3√5+√35) / 2

Then I divided by 2, and got: 3+√7+1.5√5+.5√35

Basically I have no idea what to do from here, because it says simplify it - but to me, it looks like I have complicated it even more than it was in its original form :L

Please help! Thanks in advance :smile:
Reply 1
Avatar for TenOfThem
TenOfThem
18
Original post by ERdoctor
Simplify (2+√5) / (3-√7)

I got stuck on this, I tried to rationalise the denominator and got: (6+2√7+3√5+√35) / 2

Then I divided by 2, and got: 3+√7+1.5√5+.5√35

Basically I have no idea what to do from here, because it says simplify it - but to me, it looks like I have complicated it even more than it was in its original form :L

Please help! Thanks in advance :smile:


Leave it over the 2 and that is fine
Reply 2
Avatar for TenOfThem
TenOfThem
18
Original post by Stardust Mirage
Answer is 14/2 which is 7 I think. 2root7 is root14 then just add all roots together and simplify.


???

2root7 = root28 not root14

What do you mean by add the roots
Reply 3
Avatar for ak9779
ak9779
9
Original post by Stardust Mirage
Answer is 14/2 which is 7 I think. 2root7 is root14 then just add all roots together and simplify.


wowwww don't follow this advice OP. Your answer is correct - leave it over 2.
Sorry op I was being an idiot just then so I deleted the message.
(edited 12 years ago)
Reply 5
Avatar for arra
arra
7
How is 2root7 = 14?
Just leave it how it is. it's right.
Reply 7
Avatar for TenOfThem
TenOfThem
18
Original post by Stardust Mirage
Sorry op I was being an idiot just then so I deleted the message.


Hi Stardust ... we were a bit dismissive then ... do you know what you were doing wrong?
Reply 8
Avatar for ERdoctor
ERdoctor
OP
9
Thanks everyone :smile: No problem stardust.

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