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

Toán Lớp 8: Rút gọn biểu thức: a)2(x-1)^3-(3x-2)(2+3x)+15x^2 b)(x-2)^2-(x-3)(x-1)

Toán Lớp 8: Rút gọn biểu thức:
a)2(x-1)^3-(3x-2)(2+3x)+15x^2
b)(x-2)^2-(x-3)(x-1)

Comments ( 2 )

  1. Giải đáp:
    a. 2(x-1)^3-(3x-2)(2+3x)+15^2
    = 2(x^3-3x^2+3x-1)-9x^2+4+15^2
    = 2x^3-6x^2+6x-2-9x^2+4+15^2
    = 2x^3+6x+2
    b. (x-2)^2-(x-3)(x-1)
    = x^2-4x+4-x^2+x+3x-3
    = 1
    text{~ Học Tốt Nha ~}

  2. a, 2(x-1)³-(3x-2)(2+3x)+15x²
    = 2(x³-3x²+3x-1)-[(3x)²-2²]+15x²
    = 2x³-6x²+6x-2-9x²+4+15x²
    = 2x³+6x+2
    b, (x-2)²-(x-3)(x-1)
     = x²-4x+4-(x²-4x+3)
     = x²-4x+4-x²+4x-3
     = 1

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

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