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Multiplying surds confusion

EDIT: Subtracting!

Simplify: 6/(rt)3 - 8/(2(rt)2) rt = root

I rationalised each fraction separately first so:
6/(rt)3 -> 6/(rt)3 x (rt)3/(rt)3 -> 6(rt)3/3

8/2(rt)2 -> 8/2(rt)2 x 2(rt)2/2(rt)2 -> 16(rt)2/8 -> 8(rt)2

Is this correct working so far? The end answer is supposed to be 2((rt)3 - (rt)2) apologies in advance for the weird way I've worded this, if I used latex I'd be making mistakes everywhere!
(edited 11 years ago)
Original post by Magenta96
EDIT: Subtracting!

Simplify: 6/(rt)3 - 8/(2(rt)2) rt = root

I rationalised each fraction separately first so:
6/(rt)3 -> 6/(rt)3 x (rt)3/(rt)3 -> 6(rt)3/3

8/2(rt)2 -> 8/2(rt)2 x 2(rt)2/2(rt)2 -> 16(rt)2/8 -> 8(rt)2

Is this correct working so far? The end answer is supposed to be 2((rt)3 - (rt)2) apologies in advance for the weird way I've worded this, if I used latex I'd be making mistakes everywhere!


You are making a bit of a mess of this.

Your first term is right but not fully simplified.

Your second term is wrong - try dividing 8 by 2 at outset!
Reply 2
Avatar for Magenta96
Magenta96
OP
16
Original post by Mr M
You are making a bit of a mess of this.

Your first term is right but not fully simplified.

Your second term is wrong - try dividing 8 by 2 at outset!


so the first term would simplify to, 2(rt)3? I still can't seem to get the second term right, because I keep getting a root of 2 inside which then means I can't subtract the terms
Original post by Magenta96
so the first term would simplify to, 2(rt)3? I still can't seem to get the second term right, because I keep getting a root of 2 inside which then means I can't subtract the terms


822=42=?\displaystyle \frac{8}{2 \sqrt 2}=\frac{4}{\sqrt 2} = ?
Reply 4
Avatar for Magenta96
Magenta96
OP
16
Original post by Mr M
822=42=?\displaystyle \frac{8}{2 \sqrt 2}=\frac{4}{\sqrt 2} = ?


after doing that I got the right answer really quickly! Thank you:smile:

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