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# Surds watch

1. I'm good with surds apart from i can't rmemeber what you need to do when adding/subtracting them from each other

eg 54^1/2 -3^1/2

cheers
2. well for the example;

√54 = √9√6

so √54 - √3 = √9√6 - √3 = 3√6 - √3 = (3√2-1)√3
3. (Original post by geekypoo)
well for the example;

√54 = √9√6

so √54 - √3 = √9√6 - √3 = 3√6 - √3 = (3√2-1)√3
I understand every bit upto and icluding 3√6-√3 but where does the (3√2-1)√3 come from
4. 3√6 - √3 = 3√(2*3) - √3 = 3√2√3 - √3 then factorise --> = (3√2-1)√3
5. From: 3√6-√3

Since √6 = √2√3
3√6-√3 = 3√2√3-√3 = (3√2-1)√3 taking √3 out as a factor
6. cheers i get it now

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