Radicals: Simplify ( 1 / 3-√8 ) ²

[iil-london]

Simplify:

( 1 / 3-√8 ) ²

A) 9+√8
B) 9+2√8
C) 9+6√8
D) 17+2√8
E) 17+6√8

Thanks.

[Sudhan]

(1/3-sq(8)^2

1/9+8-2*3*sq(8) using (a-b)^2 formula= a^2+b^2-2*a*b

1/17-6sq(8)

Multiply num & denom by 17+6 sq(8)

17 +6 sq(8)/ (17-6sq(8)) (17+6sq(8))

17+6 sq(8)/(17)^2 - (6sq(8))^2

17+6 sq(8)/ 289- 36*8

17+6 sq(8)/ 289-288

17+6 sq(8)

Hence E

Thanks

[RonPurewal]

please post the source for this question. thank you.