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

Toán Lớp 9: √7-4√3 – √(7-2√3)² √x+5=3 √(3-4x)²=3

Home/ Toán Lớp 9: √7-4√3 – √(7-2√3)² √x+5=3 √(3-4x)²=3

Toán Lớp 9: √7-4√3 – √(7-2√3)² √x+5=3 √(3-4x)²=3

Tháng Sáu 19, 2022 Toán học 1 Comment 0 views

Toán Lớp 9: √7-4√3 – √(7-2√3)²
√x+5=3
√(3-4x)²=3

Comments ( 1 )

  1. behocgioitoan
    behocgioitoan
    19 Tháng Sáu, 2022 at 6:23 chiều
    Reply
    Bạn tham khảo nhé.
    \sqrt{7-4\sqrt{3}}-\sqrt{(7-2\sqrt{3})^2}
    =\sqrt{4-2.2.\sqrt{3}+3}-|7-2\sqrt{3}|
    =\sqrt{(2-\sqrt{3})^2}-7+2\sqrt{3}
    =|2-\sqrt{3}|-7+2\sqrt{3}
    =2-\sqrt{3}-7+2\sqrt{3}
    =\sqrt{3}-5
    $\\$
    \sqrt{x+5}=3(x>=-5)
    =>x+5=3^2
    =>x=9-5
    =>x=4(\text{Thỏa mãn})
    Vậy x=4
    $\\$
    \sqrt{(3-4x)^2}=3
    <=>|3-4x|=3
    <=>[(3-4x=3),(3-4x=-3):}
    <=>[(4x=0),(4x=6):}
    <=>$\left[\begin{matrix} x=0 \\ x=\dfrac{3}{2}\end{matrix}\right.$
    Vậy x\in{0;3/2}
     

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

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