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

Toán Lớp 9: Tính $\frac{6}{√11+3}$-$\frac{6}{√11-3}$

Toán Lớp 9: Tính
$\frac{6}{√11+3}$-$\frac{6}{√11-3}$

Comments ( 2 )

  1. Giải đáp + Lời giải và giải thích chi tiết:
     6/( sqrt {11} + 3 ) – 6/( sqrt {11} – 3 )
    = ( 6 ( sqrt {11} – 3 ) )/( ( sqrt {11} + 3 )( sqrt {11} – 3 ) ) – ( 6 ( sqrt {11} + 3 ) )/( ( sqrt {11} + 3 )( sqrt {11} – 3 ) )
    = ( 6 ( sqrt {11} – 3 ) )/( 11 – 9 ) – ( 6 ( sqrt {11} + 3 ) )/( 11 – 9 )
    = ( 6 ( sqrt {11} – 3 ) )/2 – ( 6 ( sqrt {11} + 3 ) )/2
    = 3 ( sqrt {11} – 3 ) – 3 ( sqrt {11} + 3 )
    = 3 sqrt {11} – 9 – 3 sqrt {11} – 9
    = -18

  2. Giải:     $\frac{6}{\sqrt{11}+3}-\frac{6}{\sqrt{11}-3}$
             $=\frac{6(\sqrt{11}-3)}{(\sqrt{11}+3)(\sqrt{11}-3)}-\frac{6(\sqrt{11}+3)}{(\sqrt{11}-3)(\sqrt{11}+3)}$
             $=\frac{(6\sqrt{11}-18)-(6\sqrt{11}+18)}{11-9}$
             $=\frac{6\sqrt{11}-18-6\sqrt{11}-18}{2}$
             $=\frac{-36}{2}$
             $=-18$
    $\sqrt[Chúc]{\frac{Bạn}{∆_{Học}}}π^{Tốt}$

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

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