Hey there! Sign in to join this conversationNew here? Join for free
 You are Here: Home >< Maths

# Surds Watch

Announcements
1. So there's two questions that are confusing me:

1) Simplify 3/sqrt(63)

I did 3/3 sqrt(7) then cancelled the 3's to give sqrt(7) but it says in the book the answer should be sqrt(7)/7

2) Rationalise the denominator: 3/sqrt(3)-2

I multiplied it by sqrt(3)+2/sqrt(3)+2 and got 3 sqrt(3)+6 but the answer book says it should be -3 sqrt(3)-6

Thanks!
2. (Original post by Qaiys)
So there's two questions that are confusing me:

1) Simplify 3/sqrt(63)

I did 3/3 sqrt(7) then cancelled the 3's to give sqrt(7) but it says in the book the answer should be sqrt(7)/7
The is in the denominator

So you have
3. When you cancel the threes you have
4. (Original post by Qaiys)

2) Rationalise the denominator: 3/sqrt(3)-2

I multiplied it by sqrt(3)+2/sqrt(3)+2 and got 3 sqrt(3)+6 but the answer book says it should be -3 sqrt(3)-6
Using LaTeX will make your posts clearer

You have

Which gives

Reply
Submit reply
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: July 14, 2014
Today on TSR

### Things NOT to do at uni

Have you done any of these?

### How much revision have yr12s done?

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Useful resources

## Make your revision easier

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

Can you help? Study help unanswered threads

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.