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

Toán Lớp 9: a) √2 + √8 + √50 b) 4√3 + √27 – √45 + √5 NHAnh nÀo Rút gọn thôi

Toán Lớp 9: a) √2 + √8 + √50
b) 4√3 + √27 – √45 + √5
NHAnh nÀo Rút gọn thôi

Comments ( 2 )

  1. a) \sqrt{2}+\sqrt{8}+\sqrt{50}
    =\sqrt{2}+\sqrt{2^{2}.2}+\sqrt{5^{2}.2}
    =\sqrt{2}+2\sqrt{2}+5\sqrt{2}
    =8\sqrt{2}
    b) 4\sqrt{3}+\sqrt{27}-\sqrt{45}+\sqrt{5}
    =4\sqrt{3}+\sqrt{3^{2}.3}-\sqrt{3^{2}.5}+\sqrt{5}
    =4\sqrt{3}+3\sqrt{3}-3\sqrt{5}+\sqrt{5}
    =7\sqrt{3}-2\sqrt{5}
     

  2. \sqrt{2} + \sqrt{8} + \sqrt{50}
    = \sqrt{2} + 2\sqrt{2} + 5\sqrt{2}
    = (\sqrt{2} + 2\sqrt{2}) + 5\sqrt{2}
    = 3\sqrt{2} + 5\sqrt{2}
    = 8\sqrt{2}
    _______________________
    4\sqrt{3} + \sqrt{27} – \sqrt{45} + \sqrt{5}
    = 4\sqrt{3} + 3\sqrt{3} – 3\sqrt{5} + \sqrt{5}
    = (4\sqrt{3} + 3\sqrt{3}) – (3\sqrt{5} + \sqrt{5})
    = 7\sqrt{3} – 4\sqrt{5}
    = – 4\sqrt{5} + 7\sqrt{3}

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

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