Write 6/Ö3 + Ö27 in the form kÖ3

The answer is 2Ö3 but I don't get how...

NOTE: Ö = square root (the proper square root sign won't show up)

Posted Sat 4th June, 2011 @ 13:35 by

ShaimaaEdited by

Shaimaa on Sat 4th June, 2011 @ 13:36

I got 2 square root 3 when i divided 6 square root 3 and square root 27 not plused them, is it def plus?

Answered Sat 4th June, 2011 @ 13:52 by

Lamise Hassan
I am using & as squareroot

Take 6/&3 and times by &3/&3 to put the surd on top:

6/&3 x &3/&3 = 6&3/3 = 2&3

And &27 = &(9 x3) = 3&3

Therefore putting the equation together:

2&3 + 3&3 = 5&3

Are you sure that is the right answer?

Answered Sat 4th June, 2011 @ 13:53 by

Michelle
Yep, its definatley adding the two expressions

btw its 6 divided by square root 3 (add square root 27)

Answered Sat 4th June, 2011 @ 13:54 by

Shaimaa
been trying to do this too. thought it was wrong but i thought maybe i was doing the wrong thing.

6/root 3 gives 2 root three

Answered Sat 4th June, 2011 @ 15:37 by

Pui Pui
Sorry Lamise! 'he' is just the general term (sounds sexist :S)..

As long as the answer is 5 root 3, I get it, I would explain but maybe I'd really confuse ppl. And plus, it has been explain like, 3 times.

:)

Answered Sun 5th June, 2011 @ 18:33 by

Shaimaa
I'm using r as square root.

6/r3+r27.

Firstly, rationalise the denominator.

6/r3 x r3/r3 = 6r3/3 = 2r3.

Then, simplify r27

r27=r9r3=3r3.

Add them together.

3r3+2r3=5r3.

Answer = 5r3

Answered Sun 5th June, 2011 @ 19:33 by

Sarah
Thanks that is a good way of doing it.. but the answer is def 2 square root 3. I'm hoping something like this doesn't come up on the exam :S And that they got the answer wrong

Answered Sat 4th June, 2011 @ 13:57 by

Shaimaa
I've tried this so much and it doesnt make sense, wheres the question from?

Answered Sat 4th June, 2011 @ 14:31 by

Lamise Hassan
if you rationalise the first past you get 2root3, are you sure that isn't the answer? is it a 2 part question?

if you type it into the calculator, it comes up with 9root3.

Answered Sat 4th June, 2011 @ 14:41 by

Kelly:)
5 root 3 is 100% right answer, my maths teacher done it, the answer scheme MUST be wrong, i'm gonna upload the answer to my resources if u wna check it out

Answered Sat 4th June, 2011 @ 16:43 by

Lamise HassanEdited by

Lamise Hassan on Sat 4th June, 2011 @ 16:43

Yes, maybe it is wrong.. It's from a AQA higher Maths revision guide. And, it makes more sense 5 root 3.. Thank you. So basically; you simplify root 27 and then add it to the rationalised 6 over root 3?..

Answered Sat 4th June, 2011 @ 17:11 by

Shaimaa
but surely if you rationalise the 6 over root 3 you must have to times the root 27 by root 3 over root 3

Answered Sat 4th June, 2011 @ 17:14 by

Pui Pui
**Lamise Hassan** has made a document of how to work it out, check it out. I think my explanation isn't quite right.. so it's better if you see it step by step on the word document he's made..

Answered Sat 4th June, 2011 @ 17:28 by

Shaimaa
But you have to simplify the root 27 first

Answered Sat 4th June, 2011 @ 17:29 by

Lamise Hassan
Answered Sat 4th June, 2011 @ 19:12 by

Lamise Hassan
Or you could just look at my explanation above 4 hours ago!!

Answered Sat 4th June, 2011 @ 20:08 by

Michelle