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# Surds question watch

1. How does rationalising
(the square root of) 2 - (square root of)3 / (square root of) 2 - (square root of) 3 equal -1?
Shouldnt ir at least equal 1?
Can you please show me how this is done.?

P.s sorry if you don't understand what I mean, I can type, or copy and paste square root signs.
2. You 100% it's -1 ? If it's from a book then there is a chance it might be wrong. I tired it and it only gave me 1
3. If what you typed is correct, It does equal 1.
4. Can anyone help with this ? Trying to self teach myself A level maths -

How does the sq root of 17 minus sq root of 11 all divided by sq root of 17 PLUS the sq root of 11 = 14 minus sq root of 187 all over 3 ??

I'm rationalising the denominator by multiplying by sq root of 17 minus sq root of 11 over the same but I can't understand how you don't get minus 2 x sq root of 11 a 17 on the top line ?
5. (Original post by chocolate_ee)
Can anyone help with this ? Trying to self teach myself A level maths -

How does the sq root of 17 minus sq root of 11 all divided by sq root of 17 PLUS the sq root of 11 = 14 minus sq root of 187 all over 3 ??

I'm rationalising the denominator by multiplying by sq root of 17 minus sq root of 11 over the same but I can't understand how you don't get minus 2 x sq root of 11 a 17 on the top line ?
sorry - should have given my full answer which was 18 minus 2 x sq root of 187 all over 8
6. Doh ... dumb error , I was subtracting 11 from 17 and getting 8 - Ha ha !!

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