You are Here: Home >< Maths

# Maths year 11 Watch

1. (Original post by z_o_e)
I need an introduction haha I know a bit of this

Just expand the brackets as you would with normal algebra.

The final answer for the first one is 18+6√5

The rules for surds have already been posted above, try the other questions out.

I'll do the last one which involves rationalising the denominator.

Edit: my answer is slightly wrong I wrote 3√5 instead of 6√5
2. (Original post by B_9710)
There are very simple rules you need to follow to answer all of these questions.
and also
.
Your messages come in different forms latex? I'm using my phone for tsr x

Posted from TSR Mobile
3. (Original post by z_o_e)
Your messages come in different forms latex? I'm using my phone for tsr x

Posted from TSR Mobile
Spoiler:
Show
4. (Original post by 34908seikj)
Spoiler:
Show
Where did you get this 9=3 from?

Posted from TSR Mobile
Attached Images

5. (Original post by z_o_e)
Where did you get this 9=3 from?

Posted from TSR Mobile
√9 = 3

What's 3^2 ? It's 9. So therefore √9 = 3
6. (Original post by 34908seikj)
√9 = 3

What's 3^2 ? It's 9. So therefore √9 = 3
OOOH. SO THIS IS SQUARE ROOT??
Ohh

And I didn't understand what I do after this..

Posted from TSR Mobile
Attached Images

7. (Original post by z_o_e)
OOOH. SO THIS IS SQUARE ROOT??
Ohh

And I didn't understand what I do after this..

Posted from TSR Mobile
Multiply. Remember if you multiply the same two numbers together it's equivalent to squaring them. Since you're multiplying a square root number by the same square root number, the square root cancels out and you're just left with the number

e.g. √3*√3 = 3 - or you can think of it like √3*√3 = √9 and √9 = 3

√3 * √15 = √45 since it's just 3*15 under a root. Then you can simply the √45
8. (Original post by 34908seikj)
Multiply. Remember if you multiply the same two numbers together it's equivalent to squaring them. Since you're multiplying a square root number by the same square root number, the square root cancels out and you're just left with the number

e.g. √3*√3 = 3 - or you can think of it like √3*√3 = √9 and √9 = 3

√3 * √15 = √45 since it's just 3*15 under a root. Then you can simply the √45
Do I simplify 90?

Posted from TSR Mobile
Attached Images

9. (Original post by z_o_e)
Do I simplify 90?

Posted from TSR Mobile
No, you have two pairs of √45 so it would be 2√45, not √90, you CAN'T add surds like that.
10. (Original post by 34908seikj)
No, you have two pairs of √45 so it would be 2√45, not √90, you CAN'T add surds like that.
Can you do this part please?

On paper and shown it out please x

Posted from TSR Mobile
Attached Images

12. (Original post by z_o_e)
Can you do this part please?

On paper and shown it out please x

Posted from TSR Mobile
So you have 3 + √45 + √45 + 15

: 18 + 2√45

√45 Simplifies down to 3√5

So now you have 18 + (2)(3)√5

Which gives you the final answer of 18 + 6√5
13. (Original post by 34908seikj)
So you have 3 + √45 + √45 + 15

: 18 + 2√45

√45 Simplifies down to 3√5

So now you have 18 + (2)(3)√5

Which gives you the final answer of 18 + 6√5
GOT IT !!!

Posted from TSR Mobile
Attached Images

14. (Original post by z_o_e)
GOT IT !!!

Posted from TSR Mobile
Yup! Try the other question by yourself now, see how far you get.
15. (Original post by 34908seikj)
Yup! Try the other question by yourself now, see how far you get.
I think I should learn to do these ones then move onto rationalalizing?

Posted from TSR Mobile
Attached Images

16. (Original post by z_o_e)
I think I should learn to do these ones then move onto rationalalizing?

Posted from TSR Mobile
That's right. Rationalising is really straight forward, so yes I think you should
17. (Original post by 34908seikj)
That's right. Rationalising is really straight forward, so yes I think you should
I'll do one last question on this without looking back at my notes xx

Posted from TSR Mobile
18. (Original post by 34908seikj)
That's right. Rationalising is really straight forward, so yes I think you should

Posted from TSR Mobile
Attached Images

19. I get 54+24√2

You've messed up for working out slightly; you write + for everything when some of the sums should have been multiplied.
20. (Original post by 34908seikj)
I get 54+24√2

You've messed up for working out slightly; you write + for everything when some of the sums should have been multiplied.
I corrected them in red pen.

Posted from TSR Mobile
Attached Images

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: December 10, 2016
Today on TSR

### Anxious about my Oxford offer

What should I do?

### Am I doomed because I messed up my mocks?

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

Can you help? Study help unanswered threadsStudy Help rules and posting guidelinesLaTex guide for writing equations on TSR

## 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