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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. dongoclandiem
    dongoclandiem
    19 Tháng Sáu, 2022 at 5:42 chiều
    Reply
    a) \sqrt{7-4\sqrt{3}}-\sqrt{(7-2\sqrt{3})^2}
    =\sqrt{(2-\sqrt{3})^2}-\sqrt{(7-2\sqrt{3})^2}
    =|2-\sqrt{3}|-|7-2\sqrt{3}|
    =2-\sqrt{3}-7+2\sqrt{3}
    =-5+\sqrt{3}
    b) \sqrt{x+5}=3 (x>=-5)
    ⇔x+5=9
    ⇔x=4 ™
    Vậy S={4}
    c) \sqrt{(3-4x)^2}=3 (x∈R)
    ⇔|3-4x|=3
    ⇔\(\left[ \begin{array}{l}3-4x=3\\3-4x=-3\end{array} \right.\) 
    ⇔\(\left[ \begin{array}{l}x=0(tm)\\x=\dfrac{3}{2}(tm)\end{array} \right.\) 
    Vậy S={0,3/2}

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

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