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

Toán Lớp 8: rút gọn biểu thức (x-1)(x-3)-4(2x+1)-3x^2 2x^2(x-2)+3x(x^2-x-2)-5(3-x^2)

Toán Lớp 8: rút gọn biểu thức (x-1)(x-3)-4(2x+1)-3x^2
2x^2(x-2)+3x(x^2-x-2)-5(3-x^2)

Comments ( 2 )

  1. $a)(x-1)(x-3)-4(2x+1)-3x^2$
    $=(x^2-4x+3)-(8x+4)-3x^2$
    $=x^2-4x+3-8x-4-3x^2$
    $=-2x^2-12x-1$
    $b)2x^2(x-2)+3x(x^2-x-2)-5(3-x^2)$
    $=(2x^3-4x^2)+(3x^3-3x^2-6x)-(15-5x^2)$
    $=2x^3-4x^2+3x^3-3x^2-6x-15+5x^2$
    $=5x^3-2x^2-6x-15$

  2. Giải đáp+Lời giải và giải thích chi tiết:
    (x-1)(x-3)-4(2x+1)-3x^2
    =x^2-3x-x+3-8x-4-3x^2
    =(x^2-3x^2)-(3x+x+8x)+(3-4)
    =-2x^2-12x-1
    2x^2(x-2)+3x(x^2-x-2)-5(3-x^2)
    =2x^3-4x^2+3x^3-3x^2-6x-15+5x^2
    =(2x^3+3x^3)-(4x^2+3x^2-5x^2)-6x-15
    =5x^3-2x^2-6x-15
    $\text{#LinhSad}$

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