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

Toán Lớp 7: Rút gọn biểu thức sau : ( 3x – 1 )^2 + 2( 3x – 1 )( 2x + 1 ) + ( 2x + 1 )^2 ( x^2 + 1 )( x – 3 ) – ( x – 3 )( x^2 – 1 )

Toán Lớp 7: Rút gọn biểu thức sau :
( 3x – 1 )^2 + 2( 3x – 1 )( 2x + 1 ) + ( 2x + 1 )^2
( x^2 + 1 )( x – 3 ) – ( x – 3 )( x^2 – 1 )

Comments ( 2 )

  1. Giải đáp:
     
    Lời giải và giải thích chi tiết:
    (3x-1)^2 + 2(3x-1)(2x+1) + (2x+1)^2
    = 9x^2 – 6x + 1 + 12x^2 + 2x – 2 + 4x^2 + 4x + 1
    = (9x^2+12x^2+4x^2) – (6x+2x+4x) + (1-2+1)
    = 25x^2
    (x^2+1)(x-3)-(x-3)(x^2-1)
    = x^3 – 3x^2 + x – 3 – x^3 + x + 3x^2 – 3
    = (x^3-x^3) -(3x^2+3x^2)+(x+x)-(3-3)
    = 2x -6

  2. (3x-1)^2+2(3x-1)(2x+1)+(2x+1)^2
    =9x^2-6x+1+12x^2+6x-4x-2+4x^2+4x+1
    =(9x^2+12x^2+4x^2)+(-6x+6x-4x+4x)+(1-2+1)
    =25x^2
    (x^2+1)(x-3)-(x-3)(x^2-1)
    =x^3-3x^2+x-3-x^3+x+3x^2-3
    =(x^3-x^3)+(-3x^3+3x^2)+(x+x)+(-3-3)
    =2x-6
    $\text{@ThanhTruc2008}$

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