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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 9: Tính $\frac{6}{\sqrt{2}-\sqrt{3}+3}$

Toán Lớp 9: Tính
$\frac{6}{\sqrt{2}-\sqrt{3}+3}$

Comments ( 2 )

  1. Giải đáp+Lời giải và giải thích chi tiết:
    \frac{6}{\sqrt{2}-\sqrt{3}+3}
    =\frac{6(\sqrt{2}-\sqrt{3}-3)}{(\sqrt{2}-\sqrt{3})^2-3^2}
    =\frac{6\sqrt{2}-6\sqrt{3}-18}{3-2\sqrt{6}+2-9}
    =\frac{6\sqrt{2}-6\sqrt{3}-18}{-2\sqrt{6}-4}
    =\frac{-2(3\sqrt{2}+3\sqrt{3}+9)}{-2(\sqrt{6}+2)}
    =\frac{-3\sqrt{2}+3\sqrt{3}+9}{\sqrt{6}+2}
    =\frac{(-3\sqrt{2}+3\sqrt{3}+9)(\sqrt{6}-2)}{6-4}
    =\frac{-6\sqrt{3}+6\sqrt{2}+9\sqrt{2}-6\sqrt{3}+9\sqrt{6}-18}{2}
    =\frac{-12\sqrt{3}+15\sqrt{2}+9\sqrt{6}-18}{2}
     

  2. \frac{6}{\sqrt{2}-\sqrt{3}+3}
    =\frac{6}{3+\sqrt{2}-\sqrt{3}}
    =\frac{6(3+\sqrt{2}+\sqrt{3})}{(3+\sqrt{2})^2-\sqrt{3}^2}
    =\frac{18+6\sqrt{2}+6\sqrt{3}}{9+6\sqrt{2}+2-3}
    =\frac{18+6\sqrt{2}+6\sqrt{3}}{8+6\sqrt{2}}
    =\frac{2(9+3\sqrt{2}+3\sqrt{3})}{2(4+3\sqrt{2})}
    =\frac{(9+3\sqrt{2}+3\sqrt{3})(4-3\sqrt{2})}{4^2-(3\sqrt{2})^2}
    =\frac{36-27\sqrt{2}+12\sqrt{2}-18+12\sqrt{3}-9\sqrt{6}}{16-18}
    =\frac{-18+15\sqrt{2}+9\sqrt{6}-12\sqrt{3}}{2}

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222-9+11+12:2*14+14 = ? ( )