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

Toán Lớp 8: a/ x(x-5)+x-5 = 0 b/ 7x(x-4) – x+4=0 c/ (x^2-4x)-5x+20=0

Home/ Toán Lớp 8: a/ x(x-5)+x-5 = 0 b/ 7x(x-4) – x+4=0 c/ (x^2-4x)-5x+20=0

Toán Lớp 8: a/ x(x-5)+x-5 = 0 b/ 7x(x-4) – x+4=0 c/ (x^2-4x)-5x+20=0

Tháng Sáu 29, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: a/ x(x-5)+x-5 = 0
b/ 7x(x-4) – x+4=0
c/ (x^2-4x)-5x+20=0

Comments ( 2 )

  1. buianhtuan
    buianhtuan
    29 Tháng Sáu, 2022 at 12:02 chiều
    Reply
    Giải đáp+Lời giải và giải thích chi tiết:
    a)
    x(x – 5) + x – 5 = 0
    x(x – 5) + (x – 5) = 0
    (x – 5)(x + 1) = 0
    => x- 5 = 0 hoặc x + 1 = 0
    => x = 5 hoặc x = -1
    b)
    7x(x – 4) – x + 4 = 0
    7x(x – 4) – (x – 4) = 0
    (x – 4)(7x – 1) = 0
    => x – 4 = 0 hoặc 7x – 1 = 0
    => x = 4 hoặc x = 1/7
    c)
    (x^2-4x)-5x+20=0
    x(x – 4) – (5x – 20) = 0
    x(x – 4) – 5(x – 4) = 0
    (x – 4)(x – 5) = 0
    => x – 4 = 0 hoặc x – 5 = 0
    => x = 4 hoặc x = 5
    #SunHee

  2. thanhtung
    thanhtung
    29 Tháng Sáu, 2022 at 12:02 chiều
    Reply
    $\\a,\\x(x-5)+x-5=0\\⇔ x (x-5)+(x-5)=0\\⇔ (x-5)(x+1)=0\\⇔\left[ \begin{array}{l}x-5=0\\x+1=0\end{array} \right.\\⇔\left[ \begin{array}{l}x=5\\x=-1\end{array} \right.\\\text{Vậy}x=5,x=-1\\b,\\7x(x-4)-x+4=0\\⇔ 7x (x-4)-(x-4)=0\\⇔ (x-4)(7x-1)=0\\⇔\left[ \begin{array}{l}x-4=0\\7x-1=0\end{array} \right.\\⇔\left[ \begin{array}{l}x=4\\x=\dfrac{1}{7}\end{array} \right.\\\text{Vậy}x=4,x=\dfrac{1}{7}\\c,\\(x^2-4x)-5x+20=0\\⇔ x (x-4)-5(x-4)=0\\⇔ (x-4)(x-5)=0\\⇔\left[ \begin{array}{l}x-4=0\\x-5=0\end{array} \right.\\⇔\left[ \begin{array}{l}x=4\\x=5\end{array} \right.\\\text{Vậy}x=4,x=5$
     

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

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