Register Now

Login

Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

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

Toán Lớp 8: (x-1)^3-(x+2) (x+1)^3-5x(x+3)(x-3)

Toán Lớp 8: (x-1)^3-(x+2)
(x+1)^3-5x(x+3)(x-3)

Comments ( 2 )

  1. (x – 1)^3 – (x + 2)
    = x^3 – 3x^2 + 3x – 1 – x – 2
    = x^3 – 3x^2 + 2x – 3
    (x+1)^3-5x(x+3)(x-3)
    = x^3 + 3x^2 + 3x + 1 – 5x(x^2 – 9)
    = x^3 + 3x^2 + 3x + 1 – 5x^3 + 45x
    = -4x^3 + 3x^2 + 48x + 1

  2. Bài làm :
    (x-1)^3-(x+2)
    =x^3-3.x^2 . 1+3.x.1^2-1^3-x-2
    =x^3-3x^2+3x-1-x-2
    =x^3-3x^2+(3x-x)+(-1-2)
    =x^3-3x^2+2x-3
    $\\$
    (x+1)^3-5x(x+3)(x-3)
    =x^3+3.x^2 . 1+3.x.1^2+1-5x.(x^2-3^2)
    =x^3+3x^2+3x+1-5x^3+45x
    =(x^3-5x^3)+3x^2+(3x+45x)+1
    =-4x^3+3x^2+48x+1

Leave a reply

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