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

Toán Lớp 8: Tìm x: a) (2x – 8)2 = 144 b) 5x^2 -3x(5x+1)+10x^2=27

Home/ Toán Lớp 8: Tìm x: a) (2x – 8)2 = 144 b) 5x^2 -3x(5x+1)+10x^2=27

Toán Lớp 8: Tìm x: a) (2x – 8)2 = 144 b) 5x^2 -3x(5x+1)+10x^2=27

Tháng Sáu 11, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: Tìm x:
a) (2x – 8)2 = 144
b) 5x^2 -3x(5x+1)+10x^2=27

Comments ( 2 )

  1. lyly98
    lyly98
    11 Tháng Sáu, 2022 at 1:45 sáng
    Reply
    $1)(2x – 8)^2 =  144 $
    $<=>\left[\begin{matrix} 2x-8=12\\ 2x-8=-12\end{matrix}\right.$
    $<=>\left[\begin{matrix} 2x=20\\ 2x=-4\end{matrix}\right.$
    $<=>\left[\begin{matrix} x=10\\ x=-2\end{matrix}\right.$
    Vậy $x=10$ hoặc $x=-2$
    $b)  5x^2 -3x(5x+1)+10x^2=27$
    $<=>5x^2-15x^2-3x+10x^2=27$
    $<=>-3x=27$
    $<=>x=-9$
    Vậy $x=-9$
     

  2. thaolanphuobg
    thaolanphuobg
    11 Tháng Sáu, 2022 at 1:44 sáng
    Reply
    a) (2x-8)^2=144
    <=>(2x-8)^2-144=0
    <=>(2x-8-12)(2x-8+12)=0
    <=>(2x-20)(2x+4)=0
    <=>4(x-10)(x+2)=0
    <=>\(\left[ \begin{array}{l}x-10=0\\x+2=0\end{array} \right.\) 
    <=>\(\left[ \begin{array}{l}x=10\\x=-2\end{array} \right.\) 
    Vậy x=10 hoặc x=-2
    b) 5x^2-3x(5x+1)+10x^2=27
    <=>5x^2-15x^2-3x+10x^2=27
    <=>-3x=27
    <=>x=-9
    Vậy x=-9

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

Khánh Ly

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