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

Toán Lớp 8: 6) 8x^3 – 12x^2 + 6x – 1 = 0 7) 2(x+3) – x^2 -3x = 0 8) (4x – 3^)2 – 3x(3 – 4x) = 0 9) x^3 + 27 + (x+3)(x-9) = 0 10) x^3 – 4x^2 – 9x

Home/ Toán Lớp 8: 6) 8x^3 – 12x^2 + 6x – 1 = 0 7) 2(x+3) – x^2 -3x = 0 8) (4x – 3^)2 – 3x(3 – 4x) = 0 9) x^3 + 27 + (x+3)(x-9) = 0 10) x^3 – 4x^2 – 9x

Toán Lớp 8: 6) 8x^3 – 12x^2 + 6x – 1 = 0 7) 2(x+3) – x^2 -3x = 0 8) (4x – 3^)2 – 3x(3 – 4x) = 0 9) x^3 + 27 + (x+3)(x-9) = 0 10) x^3 – 4x^2 – 9x

Tháng Mười 26, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: 6) 8x^3 – 12x^2 + 6x – 1 = 0
7) 2(x+3) – x^2 -3x = 0
8) (4x – 3^)2 – 3x(3 – 4x) = 0
9) x^3 + 27 + (x+3)(x-9) = 0
10) x^3 – 4x^2 – 9x + 36 = 0

Comments ( 2 )

  1. thanhbinh2k5
    thanhbinh2k5
    26 Tháng Mười, 2022 at 8:10 chiều
    Reply

    đây nha nhớ cho mình ctlhn và vote cho mình nka
    toan-lop-8-6-8-3-12-2-6-1-0-7-2-3-2-3-0-8-4-3-2-3-3-4-0-9-3-27-3-9-0-10-3-4-2-9

  2. ngochuong2k2
    ngochuong2k2
    26 Tháng Mười, 2022 at 8:10 chiều
    Reply
    Giải đáp:
    16) x = 1/2
    7) x ∈ { – 3 ; 2 }
    8) x ∈ { 3/4 ; 3/7 }
    9) x ∈ { – 3 ; 0 ; 2 }
    10) x ∈ { – 3 ; 3 ; 4 }
    Lời giải và giải thích chi tiết:
    6) 8x^3 – 12x^2 + 6x – 1 = 0
    => ( 2x )^3 – 3 . ( 2x )^2 . 1 + 3 . 2x . 1 – 1^3 = 0
    => ( 2x – 1 )^3 = 0
    => 2x – 1 = 0 => 2x = 1 => x = 1/2
    Vậy x = 1/2
    7) 2 . ( x + 3 ) – x^2 – 3x = 0
    2 . ( x + 3 ) – x . ( x + 3 ) = 0
    => ( x + 3 )( 2 – x ) = 0
    => \(\left[ \begin{array}{l}x+3=0\\2-x =0\end{array} \right.\) 
    => \(\left[ \begin{array}{l}x=-3\\x=2\end{array} \right.\) 
    Vậy x ∈ { – 3 ; 2 }
    8) ( 4x – 3 )^2 – 3x . ( 3 – 4x ) = 0
    => ( 4x – 3 )( 4x – 3 ) + 3x . ( 4x – 3 ) = 0
    => ( 4x – 3 )( 4x – 3 + 3x ) = 0
    => ( 4x – 3 )( 7x – 3 ) = 0
    Trường hợp 1 :
    4x – 3 = 0
    => 4x = 3 => x = 3/4
    Trường hợp 2 :
    7x – 3 = 0
    => 7x = 3
    => x = 3/7
    Vậy x ∈ { 3/4 ; 3/7 }
    9) x^3 + 27 + ( x + 3 )( x – 9 ) = 0
    => x^3 + 3^3 + ( x + 3 )( x – 9 ) = 0
    => ( x + 3 )( x^2 – 3x + 3^2 ) + ( x + 3 )( x – 9 ) = 0
    => ( x + 3 )( x^2 – 3x + 9 + x – 9 ) = 0
    => ( x + 3 )( x^2 – 2x ) = 0
    => x . ( x – 2 )( x + 3 ) = 0
    => $\left[\begin{matrix} x=0\\x-2=0\\ x+3=0\end{matrix}\right.$
    => $\left[\begin{matrix} x=0\\x=2\\ x=- 3\end{matrix}\right.$
    Vậy x ∈ { – 3 ; 0 ; 2 }
    10) x^3 – 4x^2 – 9x + 36 = 0
    ( x^3 – 9x ) – ( 4x^2 – 36 ) = 0
    => x . ( x^2 – 9 ) – 4 . ( x^2 – 9 ) = 0
    => ( x^2 – 9 )( x – 4 ) = 0
    => ( x – 3 )( x + 3 )( x – 4 ) = 0
    =>  $\left[\begin{matrix} x-3=0\\x+3=0\\ x-4=0\end{matrix}\right.$
    => $\left[\begin{matrix} x=3\\x=- 3\\ x=4\end{matrix}\right.$
    Vậy x ∈ { – 3 ; 3 ; 4 }

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

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