Question

Упростите выражение: 7√2 - 3√8 + 4√18; (√90 - √40) * √10;


(3√5 - 2)²; (7√2-3√3)(7√2+3√3).


Cрочно надо! пожалуйста помогите

Answer 1

$7 sqrt{2} - 3 sqrt{4 times 2} + 4 sqrt{9 times 2} = \ 7 sqrt{2} - 3 times 2 sqrt{3} + 4 times 3 sqrt{2} = \ 7 sqrt{2} - 6 sqrt{2} + 12 sqrt{2} = 13 sqrt{2 } \ \ ( sqrt{90} - sqrt{40} ) times sqrt{10} = \ sqrt{900} - sqrt{400} = 30 - 20 = 10 \ \ {(3 sqrt{5} - 2) }^{2} = \ {(3 sqrt{5}) }^{2} - 2 times 3 sqrt{5} times 2 + {2}^{2} = \ 45 - 6 sqrt{5} + 4 = 49 - 6 sqrt{5} \ \ (7 sqrt{2} - 3 sqrt{3} )(7 sqrt{2} + 3 sqrt{3} ) = \ {(7 sqrt{2} )}^{2} - {(3 sqrt{3} )}^{2} = \ 98 - 27 = 71$