Question 178942
{{{(sqrt(2)-3)(sqrt(2)+3)}}} Start with the given expression



Let {{{a=sqrt(2)}}} and {{{b=3}}}



{{{(a-b)(a+b)}}} Replace each {{{sqrt(2)}}} with "a" and each "3" with "b"



{{{a^2+ab-ab-b^2}}} FOIL



{{{a^2-b^2}}} Combine like terms.



{{{(sqrt(2))^2-(3)^2}}} Plug in {{{a=sqrt(2)}}} and {{{b=3}}}



{{{2-9}}} Square {{{sqrt(2)}}} to get 2 and square 3 to get 9



{{{-7}}} Combine like terms.



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Answer:



So {{{(sqrt(2)-3)(sqrt(2)+3)=-7}}}