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: (3x + 5)^2 – 9x(x – 2) + (2x – 3)^3 = (2x + 1)(4x^2 – 2x + 1) – 18x(2x – 3) có kết quả bao nhiêu…

Home/ Toán Lớp 8: (3x + 5)^2 – 9x(x – 2) + (2x – 3)^3 = (2x + 1)(4x^2 – 2x + 1) – 18x(2x – 3) có kết quả bao nhiêu…

Toán Lớp 8: (3x + 5)^2 – 9x(x – 2) + (2x – 3)^3 = (2x + 1)(4x^2 – 2x + 1) – 18x(2x – 3) có kết quả bao nhiêu…

Tháng Hai 9, 2023 Toán học 1 Comment 0 views

Toán Lớp 8: (3x + 5)^2 – 9x(x – 2) + (2x – 3)^3 = (2x + 1)(4x^2 – 2x + 1) – 18x(2x – 3) có kết quả bao nhiêu…

Comments ( 1 )

  1. bichhhathu
    bichhhathu
    9 Tháng Hai, 2023 at 3:32 sáng
    Reply
    Giải đáp:
    (3x + 5)^2 – 9x(x – 2) + (2x – 3)^3 = (2x + 1)(4x^2 – 2x + 1) – 18x(2x – 3)
    ⇔ (3x)^2 + 2.3x.5 + 5^2 – 9x^2 + 18x + (2x)^3 – 3.(2x)^2.3 + 3.2x.3^2 – 3^3 = (2x + 1)[(2x)^2 – 2x.1 + 1^2] – 36x^2 + 54x
    ⇔ 9x^2 + 30x +  25 – 9x^2 + 18x + 8x^3 – 36x^2 + 54x – 27 = (2x)^3 + 1^3 – 36x^2 + 54x
    ⇔ 9x^2 + 30x +  25 – 9x^2 + 18x + 8x^3 – 36x^2 + 54x – 27 = 8x^3 +1 – 36x^2 + 54x
    ⇔ 9x^2 + 30x +  25 – 9x^2 + 18x + 8x^3 – 36x^2 + 54x – 27 – 8x^3 – 1 + 36x^2 – 54x = 0
    ⇔ (9x^2 – 9x^2 – 36x^2 + 36x^2) + (8x^3 – 8x^3) + (30x + 18x + 54x – 54x) + (25 – 27 – 1) = 0
    ⇔ 48x – 3 = 0
    ⇒    48x    = 3
    ⇒      x      = 3/48
    ⇒      x      = 1/16
    Học tốt

Leave a reply

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

Cẩm Hiền

About Cẩm Hiền