RÚT GỌN BIỂU THỨC a) ($\sqrt{10}$ +$\sqrt{2}$ ).(6 – 2$\sqrt{5}$ ). $\sqrt{3+\sqrt{5}}$ b) $\sqrt{3 – \sqrt{5} }$ . (3 + $\sqrt{5}$ ). ($\sqrt{10}$

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RÚT GỌN BIỂU THỨC
a) ($\sqrt{10}$ +$\sqrt{2}$ ).(6 – 2$\sqrt{5}$ ). $\sqrt{3+\sqrt{5}}$
b) $\sqrt{3 – \sqrt{5} }$ . (3 + $\sqrt{5}$ ). ($\sqrt{10}$ + $\sqrt{2}$ )

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Doris 4 years 2020-10-13T12:11:01+00:00 1 Answers 958 views 1

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  1. Euphemia
    0
    2020-10-13T12:12:48+00:00
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    Đáp án:

     

    Giải thích các bước giải:

     $a)(\sqrt{10}+\sqrt{2}).(6-2\sqrt{5}).(\sqrt{3+\sqrt{5}})$

    $=\sqrt{2}.(\sqrt{5}+1).(\sqrt{5}-1)^2.(\sqrt{3+\sqrt{5}})$

    $=\sqrt{2}.(5-1).(\sqrt{5}-1).(\sqrt{3+\sqrt{5}})$

    $=(\sqrt{6+2\sqrt{5}}).4.(\sqrt{5}-1)$

    $=(\sqrt{(\sqrt{5}+1)^2}).4.(\sqrt{5}-1)$

    $=4.(\sqrt{5}-1).(\sqrt{5}+1)$

    $=4.(5-1)$

    $=4.4=16$

    $b) (\sqrt{10}+\sqrt{2}).(3+\sqrt{5}).(\sqrt{3-\sqrt{5}})$

    $=\sqrt{2}.(\sqrt{3-\sqrt{5}}).(\sqrt{5}+1).(3+\sqrt{5})$

    $=(\sqrt{6-2\sqrt{5}}).(\sqrt{5}+1).(3+\sqrt{5})$

    $=(\sqrt{(\sqrt{5}-1)^2}).(\sqrt{5}+1).(3+\sqrt{5})$

    $=(\sqrt{5}+1).(3+\sqrt{5}).(\sqrt{5}-1)$

    $=(5-1).(3+\sqrt{5})$

    $=4.(3+\sqrt{5})$

    $=12+4\sqrt{5}$

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )