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

Toán Lớp 8: Phương Pháp tách số : 1) x ² – 5x + 6 2) x ² – 9x + 20 3) x ² + x -20 4) x ² + x -12 5) 4x ² – 7x – 2

Toán Lớp 8: Phương Pháp tách số :
1) x ² – 5x + 6
2) x ² – 9x + 20
3) x ² + x -20
4) x ² + x -12
5) 4x ² – 7x – 2

Comments ( 2 )

  1. 1) x^2-5x+6
    =x^2-5x+3.2
    =(x^2-3x)+(-2x+6)
    =x(x-3)-2(x-3)
    =(x-3)(x-2)
    2) x^2-9x+20
    =x^2-3.3x+5.4
    =x(x-5)-4(x-5)
    =(x-5)(x-4)
    3) x^2+x-20
    =x^2+x-5.4
    =x(x-4)+5(x-4)
    =(x-4)(x+5)
    4) x^2+x-12
    =x^2+x-3.4
    =x(x-3)+4(x-3)
    =(x-3)(x+4)
    5) 4x^2-7x-2
    =4x(x-2)+x-2
    =(x-2)(4x+1)
     

  2. 1) x ² – 5x + 6
    = ????^2−2????−3????+6
    = (x^2 – 2x ) – ( 3x – 6 )
    = x ( x – 2 ) – 3 ( x – 2 )
    = ( x – 2 ) ( x – 3 )
    2) x ² – 9x + 20
    = ????^2−4????−5????+20
    = (x^2 – 4x ) – ( 5x – 20 )
    = x ( x – 4 ) – 5 ( x – 4)
    = ( x- 4 )( x- 5 )
    3) x ² + x -20
    = ????^2+5????−4????−20
    = ( x^2 + 5x ) – ( 4x + 20 )
    = x ( x + 5 ) – 4 ( x + 5 )
    = ( x + 5 ) ( x – 4)
    4) x ² + x -12
    = ????^2+4????−3????−12
    = (x^2 + 4x ) – ( 3x + 12 )
    = x ( x + 4 ) – 3 ( x + 4 )
    = ( x + 4 ) ( x – 3)
    5) 4x ² – 7x – 2
    = 4????^2+????−8????−2
    = ( 4x^2 + x ) – ( 8x + 2 )
    = x ( 4x + 1 ) – 2 ( 4x + 1 )
    = ( 4x + 1 ) ( x – 2)
    Mong bạn cho nhóm mình câu trả lời hay nhất nhé!
    Mình chúc bạn học tốt!!

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

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