Random surd question :) (1 Viewer)

[sapphirejudy]

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

Thank you!</SPAN>

 

[nightweaver066]

 

[dream kaka]

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

 

[sapphirejudy]

thank you guys!

 

[Internet_Police]

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)