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

Toán Lớp 8: (x-5)^2- 3x(x-2) (2x^2-3x)* (5x^2-2x+1)

Home/ Toán Lớp 8: (x-5)^2- 3x(x-2) (2x^2-3x)* (5x^2-2x+1)

Toán Lớp 8: (x-5)^2- 3x(x-2) (2x^2-3x)* (5x^2-2x+1)

Tháng Bảy 26, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: (x-5)^2- 3x(x-2)
(2x^2-3x)* (5x^2-2x+1)

Comments ( 2 )

  1. kimlien
    kimlien
    26 Tháng Bảy, 2022 at 4:48 chiều
    Reply
    Giải đáp:
    $(x-5)²-3x.(x-2)$
    $= x²-10x+25-3x²+6x$
    $= (x²-3x²)+(6x-10x)+25$
    $= -2x²-4x+25$
    $(2x²-3x).(5x²-2x+1)$
    $= 2x².(5x²-2x+1)-3x.(5x²-2x+1)$
    $= 10x^4-4x³+2x²-15x³+6x²-3x$
    $= 10x^4-(4x³+15x³)+(2x²+6x²)-3x$
    $= 10x^4-19x³+8x²-3x$

  2. truongthanhhung
    truongthanhhung
    26 Tháng Bảy, 2022 at 4:47 chiều
    Reply
    Answer
    (x – 5)^2 – 3x . (x – 2)
    = x^2 – 2 . x . 5 + 5^2 – 3x . x + 3x . 2
    = x^2 – 10x + 25 – 3x^2 + 6x
    = (x^2 – 3x^2) + (6x – 10x) + 25
    = -2x^2 – 4x + 25
    ________________________
    (2x^2 – 3x) . (5x^2 – 2x + 1)
    = 2x^2 . (5x^2 – 2x + 1) – 3x . (5x^2 – 2x + 1)
    = 10x^4 – 4x^3 + 2x^2 – 15x^3 + 6x^2 – 3x
    = 10x^4 – (4x^3 + 15x^3) + (2x^2 + 6x^2) – 3x
    = 10x^4 – 19x^3 + 8x^2 – 3x

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

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