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

Toán Lớp 9: căn (4+ 4căn3 +3)=a+b căn 3 tìm a^2 +b^2

Toán Lớp 9: căn (4+ 4căn3 +3)=a+b căn 3
tìm a^2 +b^2

Comments ( 2 )

  1. \sqrt[4+4\sqrt[3]+3]=a+b\sqrt[3]
    =>\sqrt[2^2+2.2\sqrt[3]+\sqrt[3]^2]=a+b\sqrt[3]
    =>\sqrt[(2+\sqrt[3])^2]=a+b\sqrt[3]
    =>|2+\sqrt[3]|=a+b\sqrt[3]
    =>2+\sqrt[3]=a+b\sqrt[3]
    =>a=2;b=1
    Vậy a^2+b^2=2^2+1^2=4+1=5
     

  2. \sqrt{4+4\sqrt{3}+3}=a+b\sqrt{3}
    <=>\sqrt{2^2+2.2.\sqrt{3}+(\sqrt{3})^2}=a+b\sqrt{3}
    <=>\sqrt{(2+\sqrt{3})^2}=a+b\sqrt{3}
    <=>|2+\sqrt{3}|=a+b\sqrt{3}
    <=>2+\sqrt{3}=a+b\sqrt{3}
    <=>$\begin{cases} a=2\\b=1 \end{cases}$
    =>a^2+b^2=2^2+1=4+1=5
    Vậy a^2+b^2=5

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