c1 help - simplifying

5square root5-2(4-square root5)/(4+square root5 )(4-square root5) note: you always multyplay top and denominator by (4-root5) just practice and you will get used to it!

5square root5-8+2square root5/16-5

-8+7square root5/11

sorry for the messy work out i still can't work out where the maths symbols are :frown:

Reply 3

OP

Wezzler

the first one you simplify the brackets so root6 time root 2 becomes root12 then, and then you need times the root3 in 9/root3 by itself which is root3 times root3 then you should be able to simplify from there

the second one you times the fraction by the conjugate of the denominator,
which is 4-root5.... and then simplify

Thank you very much, helped greatly, one last thing,

On the second one, i ended up with,

(5√5 – 2) x (4 - √5)

Do i simply just expand using FOIL now?

Regards

Reply 4

Wezzler

yes tell me what you got and i will check it and no problems

Reply 5

MrBlackwood

Thank you very much, helped greatly, one last thing,

On the second one, i ended up with,

(5√5 – 2) x (4 - √5)

Do i simply just expand using FOIL now?

Regards

what u ended up with is wrong.

multiply by ( 4+root5 top and denominator, then simplify :smile:

we don't want any roots in the denominator.

Reply 6

OP

Wezzler

yes tell me what you got and i will check it and no problems

20√5 - 5√10 - 2√2 - 8

Reply 7

OP

that should be 2root5

Reply 8

You're confusing me man! the 2nd question is in this form:

5√5 – 2 divided by 4 + √5

NOT multiplied

Am I invisible here lol

Reply 9

OP

Remarqable M

You're confusing me man! the 2nd question is in this form:

5√5 – 2 divided by 4 + √5

NOT multiplied

Am I invisible here lol

yes, so you end up with

5√5 -2 (times) (4 - √5)
(4 + √5) (4 - √5)

The bottom two brackets cancel out leaving us with :

(5√5 – 2) x (4 - √5)

Reply 10

MrBlackwood

yes, so you end up with

5√5 -2 (times) (4 - √5)
(4 + √5) (4 - √5)

The bottom two brackets cancel out leaving us with :

(5√5 – 2) x (4 - √5)

DON'T CANCEL ANYTING! whenever you have to simplify surds in that form NEVER cancel out. OK

You expand out the brackets! what we want is to get rid of the square root in the denominator, so that the any square root(s) is in the numerator(top). Then you simplify :smile:

by expanding the brackets.

Reply 11

OP

Remarqable M

DON'T CANCEL ANYTING! whenever you have to simplify surds in that form NEVER cancel out. OK

You expand out the brackets! what we want is to get rid of the square root in the denominator, so that the any square root(s) is in the numerator(top). Then you simplify :smile:

by expanding the brackets.

So you end up with

20√5 - 5√10 - 2√5 – 8
11

Reply 12

MrBlackwood

So you end up with

20√5 - 5√10 - 2√5 – 8
11

Incorrect expansion numerator, but nearly there :smile:

the denominator is correct

Reply 13

OP

Remarqable M

Yes, you are correct! but nearly there simplify the top now :smile:

What would simplify mate, i'm awful with surds and fractions :frown:

Reply 14

MrBlackwood

What would simplify mate, i'm awful with surds and fractions :frown:

Sorry i overlooked your mistakes.

Here is how you simplify the numerator:

(5√5 -2) x (4 - √5) divided by 11 >>>>> (expanded form) 20√5-5x5-8+2√5 divided by 11

then you just simplify 20√5+2√5-33 divided by 11 >>> 22√5-33/11 done!

remember √5x√5=5 this is valid for any real number √n x √n=n

hope this helps you! and GOODLUCK with C1
I got a B for c1 and im retaking it in january.

Reply 15

OP

Remarqable M

Sorry i overlooked your mistakes.

Ah, what did i do wrong?

Reply 16

david_man

1

i got

5root3 +3root3 +2root3

Reply 17