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

Toán Lớp 8: Tính (rút gọn ) (x-10)^2-2(x-10)(5x-3)+(5x+3) (x-2)^3-x(x-3)^2 (x-2)(x^2+2x+4)-x(x+1)(x-1) (x+3)(x^2-3x+9)-x(x^2-1)

Tháng Một 15, 2023 Toán học 2 Comments 0 views

Toán Lớp 8: Tính (rút gọn )
(x-10)^2-2(x-10)(5x-3)+(5x+3)
(x-2)^3-x(x-3)^2
(x-2)(x^2+2x+4)-x(x+1)(x-1)
(x+3)(x^2-3x+9)-x(x^2-1)

Comments ( 2 )

  1. ngoclanquynh
    ngoclanquynh
    15 Tháng Một, 2023 at 9:56 chiều
    Reply
    (x-10)^2-2(x-10)(5x-3)+(5x+3)
    =x^2-20x+100-10x^2+106x-60+5x+3
    =(x^2-10x^2)+(-20x+106x+5x)+(100-60+3)
    =-9x^2+91x+43
    $\\$
    (x-2)^3-x(x-3)^2
    =(x^3-6x^2+12x-8)-x(x^2-6x+9)
    =x^3-6x^2+12x-8-x^3+6x^2-9x
    =(x^3-x^3)+(6x^2-6x^2)+(12x-9x)-8
    =3x-8
    $\\$
    (x-2)(x^2+2x+4)-x(x+1)(x-1)
    =(x^3-8)-x(x^2-1)
    =x^3-8-x^3+x
    =(x^3-x^3)+x-8
    =x-8
    $\\$
    (x+3)(x^2-3x+9)-x(x^2-1)
    =x^3+27-x^3+x
    =(x^3-x^3)+x+27
    =x+27

  2. tonhu12
    tonhu12
    15 Tháng Một, 2023 at 9:56 chiều
    Reply
    $ a)(x-10)^2-2(x-10)(5x-3)+(5x+3)$
    $=x^2−20x+100−10x^2+106x−60+5x+3$
    $=−9x^2+91x+43$
    $b)(x-2)^3-x(x-3)^2$
    $=x^3−6x^2+12x−8−x(x^2−6x+9)$
    $=x^3−6x^2+12x−8−x^3+6x^2-9x$
    $=3x-8$
    $c)(x-2)(x^2+2x+4)-x(x+1)(x-1)$
    $=x^3−8−x(x^2−1)$
    $=x^3-8-x^3+x$
    $=x-8$
    $d)(x+3)(x^2-3x+9)-x(x^2-1)$
    $=x^3+27−x^3+x$
    $=x+27$

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

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