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

Toán Lớp 8: giúp vs các pro!!! a) [(3x-2)(x+1) – (2x+5)(x^2–1)] : (x+1) b) (2x-1)^2 – 2(2x-1)(3-x) + (3–x)^2 c) (x-1)^3 – (x+1)(x^2 – x+1) – (3x+1)

Home/ Toán Lớp 8: giúp vs các pro!!! a) [(3x-2)(x+1) – (2x+5)(x^2–1)] : (x+1) b) (2x-1)^2 – 2(2x-1)(3-x) + (3–x)^2 c) (x-1)^3 – (x+1)(x^2 – x+1) – (3x+1)

Toán Lớp 8: giúp vs các pro!!! a) [(3x-2)(x+1) – (2x+5)(x^2–1)] : (x+1) b) (2x-1)^2 – 2(2x-1)(3-x) + (3–x)^2 c) (x-1)^3 – (x+1)(x^2 – x+1) – (3x+1)

Tháng Mười Một 2, 2022 Toán học 1 Comment 0 views

Toán Lớp 8: giúp vs các pro!!!
a) [(3x-2)(x+1) – (2x+5)(x^2–1)] : (x+1)
b) (2x-1)^2 – 2(2x-1)(3-x) + (3–x)^2
c) (x-1)^3 – (x+1)(x^2 – x+1) – (3x+1)(1 -3x)

Comments ( 1 )

  1. ngoclankhue
    ngoclankhue
    2 Tháng Mười Một, 2022 at 1:51 sáng
    Reply
    Giải đáp:
     a, [(3x – 2)(x + 1) – (2x + 5)(x^2 – 1)] : (x + 1)
    =  [(3x – 2)(x + 1) – (2x + 5)(x + 1)(x – 1)] : (x + 1)
    = (x + 1)[3x – 2 – (2x + 5)(x – 1)] : (x + 1)
    = 3x – 2 – (2x + 5)(x – 1)
    = 3x – 2 – 2x^2 + 2x – 5x + 5
    = (3x + 2x – 5x) – 2x^2 + (-2 + 5)
    = -2x^2 + 3
    b, (2x – 1)^2 – 2(2x – 1)(3 – x) + (3 – x)^2
    = [(2x – 1) – (3 – x)]^2
    = (2x – 1 – 3 + x)^2
    = (3x – 4)^2
    = (3x)^2 – 2.3x.4 + 4^2
    = 9x^2 – 24x + 16
    c, (x – 1)^3 – (x + 1)(x^2 – x + 1) – (3x + 1)(1 – 3x)
    = x^3 – 3x^2 + 3x – 1 – (x^3 + 1^3) – [1^2 – (3x)^2]
    = x^3 – 3x^2 + 3x – 1 – x^3 – 1 – 1 + 9x^2
    = (x^3 – x^3) + (-3x^2 + 9x^2) + 3x + (-1 – 1- 1)
    = 6x^2 + 3x – 3

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

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