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

Toán Lớp 9: Tính: 1) 2√3 – 3√12 2) 2√2 – √5 + √18 – √20 3) 3√3 – √12 + √24 4) 2√27 – 6√48 + 4√75 5) √28 – 2√14 + √7 + √63 6) 3√5

Tháng Mười Hai 25, 2022 Toán học 2 Comments 0 views

Toán Lớp 9: Tính:
1) 2√3 – 3√12
2) 2√2 – √5 + √18 – √20
3) 3√3 – √12 + √24
4) 2√27 – 6√48 + 4√75
5) √28 – 2√14 + √7 + √63
6) 3√5 + 4√20 – 2√125

Comments ( 2 )

  1. buithaianh98
    buithaianh98
    25 Tháng Mười Hai, 2022 at 10:00 chiều
    Reply
    Hướng dẫn trả lời:
    1) 2sqrt3 – 3sqrt12
    = 2sqrt3 – 6sqrt3
    = – 4sqrt3
    2) 2sqrt2 – sqrt5 + sqrt18 – sqrt20
    = 2sqrt2 – sqrt5 + 3sqrt2 – 2sqrt5
    = (- sqrt5 – 2sqrt5) + (2sqrt2 + 3sqrt2)
    = – 3sqrt5+ 5sqrt2
    3) 3sqrt3 – sqrt12 + sqrt24
    = 3sqrt3 – 2sqrt3 + 2sqrt6
    = 2sqrt6 + sqrt3
    4) 2sqrt27 – 6sqrt48 + 4sqrt75
    = 6sqrt3 – 24sqrt3 + 20sqrt3
    = 2sqrt3
    5) sqrt28 – 2sqrt14 + sqrt7 + sqrt63
    = 2sqrt7 – 2sqrt14 + sqrt7 + 3sqrt7
    = – 2sqrt14 + (2sqrt7 + sqrt7 + 3sqrt7)
    = – 2sqrt14 + 6sqrt7
    6) 3sqrt5 + 4sqrt20 – 2sqrt125
    = 3sqrt5 + 8sqrt5 – 10sqrt5
    = sqrt5
    Giải đáp:
    1) = – 4sqrt3
    2) = – 3sqrt5+ 5sqrt2
    3) = 2sqrt6 + sqrt3
    4) = 2sqrt3
    5) = – 2sqrt14 + 6sqrt7
    6) = sqrt5

  2. thienthanh
    thienthanh
    25 Tháng Mười Hai, 2022 at 10:00 chiều
    Reply
    $\displaystyle \begin{array}{{>{\displaystyle}l}} 1.\ 2\sqrt{3} \ -\ \ 6\sqrt{3} \ =-4\sqrt{3} \ \\ 2) \ \ 2\sqrt{2} \ -\ \ \sqrt{5} \ +\ \ 3\sqrt{2} \ -\ \ 2\sqrt{5} =\ 5\sqrt{2} \ -\ \ 3\sqrt{5} \ \\ 3) \ \ 3\sqrt{3} \ -\ \ 2\sqrt{3} \ +\ \ 2\sqrt{6} =\sqrt{3} +2\sqrt{6}\\ 4) \ \ 6\sqrt{3} -\ \ 24\sqrt{3} \ +\ \ 20\sqrt{3} =2\sqrt{3}\\ 5) \ \ 2\sqrt{7} \ -\ \ 2\sqrt{14} \ +\ \ \sqrt{7} \ +\ \ 3\sqrt{7} =6\sqrt{7} -2\sqrt{14}\\ 6) \ \ 3\sqrt{5} \ +\ \ 8\sqrt{5} \ -\ \ 10\sqrt{5} =\sqrt{5} \end{array}$

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

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