Random surd question :) (1 Viewer)

sapphirejudy

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How do you do this question:
Express root(11-6root2) as a+broot2 where a and b are rational.

Thank you!</SPAN>
 

dream kaka

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keeping doing

11-6√2=a^2+2ab√2+2b^2

ab=-3
a^2+2b^2=11

then you will get a=3 b=-1 OR a=-3 b=1
 
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keeping doing

11-6√2=a^2+2ab√2+2b^2

ab=-3
a^2+2b^2=11

then you will get a=3 b=-1 OR a=-3 b=1
lol mr newb, you have to exclude the second combination ( -3+sqrt(2) is negative, and a square root cannot return a negative number)
 

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