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

Toán Lớp 7: 1) 1/4x^2 – (1/2x -4) 1/2x 2) 2x (x-1) -x (4-x) 3) 2x^2 +3 (x^2 -1) 4) x( x+1) (x+6) –x^3 5) 3 ( 1-4x) ( x-1) +4 (3x-2) (x+3)

Tháng Một 3, 2023 Toán học 2 Comments 0 views

Toán Lớp 7: 1) 1/4x^2 – (1/2x -4) 1/2x
2) 2x (x-1) -x (4-x)
3) 2x^2 +3 (x^2 -1)
4) x( x+1) (x+6) –x^3
5) 3 ( 1-4x) ( x-1) +4 (3x-2) (x+3)

Comments ( 2 )

  1. myngocla
    myngocla
    3 Tháng Một, 2023 at 9:59 sáng
    Reply
    1) 1/4x^2 – (1/2x -4) 1/2x
    =1/4x^2-1/4x^2-2x
    =-2x
    $1′)\dfrac{1}{4x^2}-(\dfrac{1}{2x}-4).\dfrac{1}{2x}$
    $=\dfrac{1}{4x^2}-\dfrac{1}{4x^2}+\dfrac{2}{x}$
    =2/x
    2) 2x (x-1) -x (4-x)
    =2x^2-2x-4x+x^2
    =3x^2-6x
    =3x(x-2)
    3) 2x^2 +3 (x^2 -1)
    =2x^2+3x^2-3
    =5x^2-3
    4) x( x+1) (x+6) –x^3
    =x(x^2+6x+x+6)-x^3
    =x^3+7x^2+6x-x^3
    =7x^2+6x
    =x(2x+6)
    5) 3 ( 1-4x) ( x-1) +4 (3x-2) (x+3)
    =3(x-1-4x^2+4x)+4(3x^2+9x-2x-6)
    =3x-3-12x^2+12x+12x^2+36x-8x-24
    =43x-27
     

  2. hoquyly
    hoquyly
    3 Tháng Một, 2023 at 9:59 sáng
    Reply
    Giải đáp+Lời giải và giải thích chi tiết:
     1) 1/(4x²) – [1/(2x) – 4] . 1/(2x)
    = 1/(4x²) – 1/(4x²) + 2/x
    = 2/x
    2) 2x(x-1) – x(4-x)
    = 2x² – 2x – 4x + x²
    = 3x² – 6x
    = 3x(x-2)
    3) 2x² + 3(x² – 1)
    = 2x² + 3x² – 3
    = 5x² – 3
    4) x(x+1)(x+6) – x³
    = x³ + 7x² + 6x – x³
    = 7x² + 6x
    = x(7x + 6)
    5) 3(1-4x)(x-1)+4(3x-2)(x+3)
    = 15x – 3 – 12x² + 12x² + 28x – 24
    = 43x – 27

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

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