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

Toán Lớp 9: $\frac{1}{√5-2}$ + $\frac{1}{√5+2}$ $\frac{10}{√11 – √6}$ + $\frac{10}{√11 + √6}$

Toán Lớp 9: $\frac{1}{√5-2}$ + $\frac{1}{√5+2}$ $\frac{10}{√11 – √6}$ + $\frac{10}{√11 + √6}$

Comments ( 2 )

  1. Giải đáp:
    $\displaystyle 2\sqrt{5} +4\sqrt{11}$
    Lời giải và giải thích chi tiết:
    $\displaystyle \begin{array}{{>{\displaystyle}l}} \frac{1}{\sqrt{5} -2} +\frac{1}{\sqrt{5} +2} +\frac{10}{\sqrt{11} -\sqrt{6}} +\frac{10}{\sqrt{11} +\sqrt{6}}\\ =\frac{\sqrt{5} +2+\sqrt{5} -2}{\left(\sqrt{5} -2\right)\left(\sqrt{5} +2\right)} +\frac{10\left(\sqrt{11} +\sqrt{6}\right) +10\left(\sqrt{11} -\sqrt{6}\right)}{\left(\sqrt{11} -\sqrt{6}\right)\left(\sqrt{11} +\sqrt{6}\right)}\\ =\frac{2\sqrt{5}}{5-4} +\frac{20\sqrt{11}}{11-6} =2\sqrt{5} +4\sqrt{11} \end{array}$ 

  2. 1/(\sqrt{5}-2)+1/(\sqrt{5}+2)+(10)/(\sqrt{11}-\sqrt{6})+(10)/(\sqrt{11}+\sqrt{6})
    =(\sqrt{5}+2+\sqrt{5}-2)/((\sqrt{5}-2)(\sqrt{5}+2))+(10(\sqrt{11}+\sqrt{6}))/((\sqrt{11}-\sqrt{6})(\sqrt{11}+\sqrt{6}))+(10(\sqrt{11}-\sqrt{6}))/((\sqrt{11}+\sqrt{6}))
    =(2\sqrt{5})/(1)+(10(\sqrt{11}+\sqrt{6}))/(5)+(10(\sqrt{11}-\sqrt{6}))/(5)
    =2\sqrt{5}+2(\sqrt{11}+\sqrt{6})+2(\sqrt{11}-\sqrt{6})
    =2\sqrt{5}+2\sqrt{11}+2\sqrt{6}+2\sqrt{11}-2\sqrt{6}
    =2\sqrt{5}+4\sqrt{11}
     

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