Question 97610
 2sqrt( 6 ) }}}+{{{ 7sqrt( 3 ) }}})({{{ 2sqrt( 6 ) }}}-{{{ 7sqrt( 3 ) }}})
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(2sqrt(6) + 7sqrt(3) (2sqrt(6) - 7sqrt(3))

= (2sqr(6))^2 - (7sqrt(3))^2

= 4*6 - 49*3

= 24 - 147

= -123
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Cheers,
Stan H.