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: Tính: a. 2x(x – 2) b. (x^2 + 1)(5 – x) c. (x – 2)(x^2 + 3x – 4)

Toán Lớp 8: Tính:
a. 2x(x – 2)
b. (x^2 + 1)(5 – x)
c. (x – 2)(x^2 + 3x – 4)

Comments ( 2 )

  1. Giải đáp+Lời giải và giải thích chi tiết:
    a)
    2x(x – 2)
    = 2x.x + 2x.(-2)
    = 2x^2 – 4x
    b)
    (x^2 + 1)(5 – x)
    = x^2 . 5 – x^2 . x + 1.5 – 1.x
    = 5x^2 – x^3 + 5 – x
    c)
    (x – 2)(x^2 + 3x – 4)
    = x.x^2 + x.3x – x.4 – 2.x^2 – 2.3x – 2. (- 4)
    = x^3 + 3x^2 – 4x – 2x^2 – 6x + 8
    = x^3 + (3x^2 – 2x^2) – (4x + 6x) + 8
    = x^3 + x^2 – 10x + 8
    #SunHee

  2. a, 2x(x-2)
    = 2x^2 – 4x
    b, (x^2 +1)(5-x)
    = 5x^2 – x^3 + 5 – x
    c, (x-2)(x^2 + 3x -4)
    = x^3 + 3x^2 – 4x – 2x^2 – 6x +8
    = x^3 + x^2 – 10x +8
     

Leave a reply

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

About Nguyệt