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

Toán Lớp 9: tính Căn 49-12√5 + Căn 49+12√5

Toán Lớp 9: tính
Căn 49-12√5 + Căn 49+12√5

Comments ( 2 )

  1. Đáp án:
     
    Giải thích các bước giải:
     

    toan-lop-9-tinh-can-49-12-5-can-49-12-5

  2. \sqrt{49 – 12\sqrt{5}} + \sqrt{49 + 12\sqrt{5}}
    = \sqrt{45 – 4\sqrt{45} + 4} + \sqrt{45 + 4\sqrt{45} + 4}
    = \sqrt{(\sqrt{45} – 2)^2} + \sqrt{(\sqrt{45} + 2)^2}
    = |\sqrt{45} – 2| + |\sqrt{45} + 2|
    = \sqrt{45} – 2 + \sqrt{45} + 2
    = 2\sqrt{45}
    = 6\sqrt{5}

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

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