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# Maths help. watch

1. How would you simplify
4 times (root 11)/5+(root 11).
2. (Original post by Maths1210)
How would you simplify
4 times (root 11)/5+(root 11).
You would try to simplify by rationalising the denominator. So you would multiply top and bottom by the conjugate of 5+(root 11).
3. (Original post by Anonymouspsych)
You would try to simplify by rationalising the denominator. So you would multiply top and bottom by the conjugate of 5+(root 11).
Okay. Then how would I be able to work out 4 (root 11) x 5+(root 11)?
4. (Original post by Maths1210)
Okay. Then how would I be able to work out 4 (root 11) x 5+(root 11)?
You want to multiply by the conjugate of 5+(root 11) which would be 5-(root 11). This means the top would turn into 4 (root 11) x 5-(root 11) and the bottom would turn into [5-(root 11)] x [5+(root 11)] .

5. (Original post by Anonymouspsych)
You want to multiply by the conjugate of 5+(root 11) which would be 5-(root 11). This means the top would turn into 4 (root 11) x 5-(root 11) and the bottom would turn into [5-(root 11)] x [5+(root 11)] .

Okay I still don't know where to go from there though.
6. (Original post by Maths1210)
Okay I still don't know where to go from there though.
would the 5 minus root 11 cancel out
7. (Original post by Maths1210)
would the 5 minus root 11 cancel out
do you not know how to expand two brackets with two terms?

For example the bottom part of the fraction would turn into

(5+root11)(5-root11) = 25 -5root11 + 5root11 - 11 = 14

notice how the root11s cancel out- this is knows as the difference of two squares.

Do the same technique with the top of the fraction and then simplify

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