Year 12s: what will be the first way you research your future options? >>

Year 12s: what will be the first way you research your future options? >>

Year 12s: what will be the first way you research your future options? >>

Expand these brackets (Surds) help

username1532593

(2+3√5)(3-√5)

Original post by eyenarbi

(2+3√5)(3-√5)

What are you struggling with?

Do you usually know how to expand brackets?

Do you know what

\sqrt5 \times \sqrt5

is?

username1532593

OP

Original post by TenOfThem

What are you struggling with?

Do you usually know how to expand brackets?

Do you know what

\sqrt5 \times \sqrt5

is?

The 3√5 how is that

Original post by eyenarbi

The 3√5 how is that

How is that what?

Could you expand (2 + 3a)(3 - a)

username1532593

OP

Original post by AlphaNick

Do it the same as you would with expanding to form a quadratic equation, bearing in mind the rules for multiplying surds.

For example,
$\sqrt{n}\cdot \sqrt{n}=n$
$\sqrt{n}\cdot -\sqrt{n}=-n$

Also, it might be helpful to realise that $3\sqrt{5}=\sqrt{3}\cdot \sqrt{3}\cdot \sqrt{5}$ and $3\cdot \sqrt{5}=3\sqrt{5}$

6-2√5+9√5-4
6-8-4
-6

is this correct i cannot understand waaaaah :frown:

:frown:

Original post by eyenarbi

6-2√5+9√5-4
6-8-4
-6

is this correct i cannot understand waaaaah :frown:

:frown:

yes
yes
yes
no

Then no, where does that come from
So, no

Can you take a look at my previous post

username1532593

OP

Original post by TenOfThem

yes
yes
yes
no

Then no, where does that come from
So, no

Can you take a look at my previous post

6 - 2√5 + 9√5 - 15

Original post by eyenarbi

6 - 2√5 + 9√5 - 15

good so far

now to deal with the surds

what is

9\sqrt5 - 2\sqrt5

username1532593

OP

Original post by TenOfThem

good so far

now to deal with the surds

what is

9\sqrt5 - 2\sqrt5

7√5 ?

Original post by eyenarbi

7√5 ?

yes

you need to tell your Y12 teacher how much you have struggled with this homework

username1532593

OP

Original post by TenOfThem

yes

you need to tell your Y12 teacher how much you have struggled with this homework

I think I've chose the wrong subject :frown:

:frown:

Study Forum Helper

Original post by eyenarbi

I think I've chose the wrong subject :frown:

:frown:

Too early to reach that conclusion.

username1532593

OP

Original post by Mr M

Too early to reach that conclusion.

I thought I'm too good at it..

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