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

Toán Lớp 8: 1.Rút gọn: a, ( x-4 )( x^2+4x+16 ) – x( x^2+5x-1 ) b, ( x-3 )( x^2+3x+9 ) – 27x( x-1 )-x^3 c, ( x-1 )^3 – ( x-3 )( x^2+3x+9 ) + 3x( x-

Home/ Toán Lớp 8: 1.Rút gọn: a, ( x-4 )( x^2+4x+16 ) – x( x^2+5x-1 ) b, ( x-3 )( x^2+3x+9 ) – 27x( x-1 )-x^3 c, ( x-1 )^3 – ( x-3 )( x^2+3x+9 ) + 3x( x-

Toán Lớp 8: 1.Rút gọn: a, ( x-4 )( x^2+4x+16 ) – x( x^2+5x-1 ) b, ( x-3 )( x^2+3x+9 ) – 27x( x-1 )-x^3 c, ( x-1 )^3 – ( x-3 )( x^2+3x+9 ) + 3x( x-

Tháng Mười Một 7, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: 1.Rút gọn:
a, ( x-4 )( x^2+4x+16 ) – x( x^2+5x-1 )
b, ( x-3 )( x^2+3x+9 ) – 27x( x-1 )-x^3
c, ( x-1 )^3 – ( x-3 )( x^2+3x+9 ) + 3x( x-1 )
d, ( x+3 )^3 – ( 2x+1 )( 4x^2-2x+1) + 7x( x^2+1 )

Comments ( 2 )

  1. ankim
    ankim
    7 Tháng Mười Một, 2022 at 10:35 sáng
    Reply
    Giải đáp:
     a, (x – 4)(x^2 + 4x + 16) – x(x^2 + 5x – 1)
    = (x – 4)(x^2 + x.4 + 4^2) – x^3 – 5x^2 + x
    = x^3 – 4^3 – x^3 – 5x^2 + x
    = (x^3 – x^3) – 5x^2 + x – 64
    = – 5x^2 + x – 64
    b, (x – 3)(x^2 + 3x + 9) – 27x(x – 1) – x^3
    =  x^3 – 3^3 – 27x^2 + 27x – x^3
    = (x^3 – x^3) – 27x^2 + 27x – 27
    = – 27x^2 + 27x – 27
    c, (x – 1)^3 – (x – 3)(x^2 + 3x + 9) + 3x(x – 1)
    = x^3 – 3x^2 . 1 + 3x. 1^2 – 1^3 – (x^3 – 3^3) + 3x^2 – 3x
    = x^3 – 3x^2 + 3x -1 – x^3 + 27 + 3x^2 – 3x
    = (x^3 – x^3) + (-3x^2 + 3x^2) + (3x – 3x) + (-1 + 27)
    = 26
    d, (x + 3)^3 – (2x + 1)(4x^2 – 2x + 1) + 7x(x^2 + 1)
    = x^3 + 3.x^2 . 3 + 3.x.3^2 + 3^3 – (2x + 1)[(2x)^2 – 2x.1 + 1^2] + 7x^3 + 7x
    = x^3 + 9x^2 + 27x + 27 – [(2x)^3 + 1^3] + 7x^3 + 7x
    = x^3 + 9x^2 + 27x + 27 – 8x^3 – 1 + 7x^3 + 7x
    = (x^3 – 8x^3 + 7x^3) + 9x^2 + (27x + 7x) + (27 – 1)
    = 9x^2 + 34x + 26

  2. lyly98
    lyly98
    7 Tháng Mười Một, 2022 at 10:35 sáng
    Reply
    #Sad
    a)
    (x-4)(x^2+4x+16)-x(x^2+5x-1)
    = x^3-64-x^3-5x^2+x
    = -5x^2+x-64
    b)
    (x-3)(x^2+3x+9)-27x(x-1)-x^3
    = x^3-27-27x^2+27x-x^3
    = -27x^2+27x-27
    c)
    (x-1)^3-(x-3)(x^2+3x+9)+3x(x-1)
    = x^3-3x^2+3x-1-x^3+27+3x^2-3x
    = 26
    d)
    (x+3)^3-(2x+1)(4x^2-2x+1)+7x(x^2+1)
    = x^3+9x^2+27x+27-8x^3-1+7x^3+7x
    = 9x^2+34x+26

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

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