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

Toán Lớp 8: Rút gọn biểu thức A =3x ( x-2) -5x ( 1-x) -8 (x^2-3) B=(2x+y)^2 +(x – y )^2 -5 (x + y) (x-y)

Toán Lớp 8: Rút gọn biểu thức
A =3x ( x-2) -5x ( 1-x) -8 (x^2-3)
B=(2x+y)^2 +(x – y )^2 -5 (x + y) (x-y)

Comments ( 2 )

  1. Giải đáp + Lời giải và giải thích chi tiết:
    A = 3x (x – 2) – 5x (1 – x) – 8(x^2 – 3)
    A = 3x^2 – 6x – 5x + 5x^2 – 8x^2 + 24
    A = -11x + 24
    $\\$
    B = (2x + y)^2 + (x – y)^2 – 5(x + y)(x – y)
    B = 4x^2 + 4xy + y^2 + x^2 – 2xy + y^2 – (5x + 5y)(x – y)
    B = 5x^2 + 2xy + 2y^2 – (5x^2 – 5xy + 5xy – 5y^2)
    B = 5x^2 + 2xy + 2y^2 – 5x^2 + 5y^2
    B = 2xy + 7y^2

  2. ~ Bạn tham khảo ~
    A =3x ( x-2) -5x ( 1-x) -8 (x^2-3)
    = 3x^2-6x – 5x + 5x^2 – 8x^2 + 24
    = -11x+24
    B=(2x+y)^2 +(x – y )^2 -5 (x + y) (x-y)
    = 4x^2+4xy + y^2 + x^2 – 2xy + y^2 – 5x^2 + 5y^2
    = 7y^2 + 2xy

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